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<h1>FindBugs Bug Descriptions</h1>
<p>This document lists the standard bug patterns reported by
<a href="http://findbugs.sourceforge.net">FindBugs</a> version 2.0.1.</p>
<h2>Summary</h2>
<table width="100%">
<tr bgcolor="#b9b9fe"><th>Description</th><th>Category</th></tr>
<tr bgcolor="#eeeeee"><td><a href="#AM_CREATES_EMPTY_JAR_FILE_ENTRY">AM: Creates an empty jar file entry</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#AM_CREATES_EMPTY_ZIP_FILE_ENTRY">AM: Creates an empty zip file entry</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_EQUALS_METHOD_SHOULD_WORK_FOR_ALL_OBJECTS">BC: Equals method should not assume anything about the type of its argument</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BIT_SIGNED_CHECK">BIT: Check for sign of bitwise operation</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#CN_IDIOM">CN: Class implements Cloneable but does not define or use clone method</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#CN_IDIOM_NO_SUPER_CALL">CN: clone method does not call super.clone()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE">CN: Class defines clone() but doesn't implement Cloneable</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#CO_ABSTRACT_SELF">Co: Abstract class defines covariant compareTo() method</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#CO_SELF_NO_OBJECT">Co: Covariant compareTo() method defined</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DE_MIGHT_DROP">DE: Method might drop exception</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DE_MIGHT_IGNORE">DE: Method might ignore exception</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_ENTRY_SETS_MAY_REUSE_ENTRY_OBJECTS">DMI: Adding elements of an entry set may fail due to reuse of Entry objects</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_RANDOM_USED_ONLY_ONCE">DMI: Random object created and used only once</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_USING_REMOVEALL_TO_CLEAR_COLLECTION">DMI: Don't use removeAll to clear a collection</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_EXIT">Dm: Method invokes System.exit(...)</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_RUN_FINALIZERS_ON_EXIT">Dm: Method invokes dangerous method runFinalizersOnExit</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ES_COMPARING_PARAMETER_STRING_WITH_EQ">ES: Comparison of String parameter using == or !=</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ES_COMPARING_STRINGS_WITH_EQ">ES: Comparison of String objects using == or !=</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_ABSTRACT_SELF">Eq: Abstract class defines covariant equals() method</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS">Eq: Equals checks for incompatible operand</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_COMPARETO_USE_OBJECT_EQUALS">Eq: Class defines compareTo(...) and uses Object.equals()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_GETCLASS_AND_CLASS_CONSTANT">Eq: equals method fails for subtypes</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_SELF_NO_OBJECT">Eq: Covariant equals() method defined</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#FI_EMPTY">FI: Empty finalizer should be deleted</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#FI_EXPLICIT_INVOCATION">FI: Explicit invocation of finalizer</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#FI_FINALIZER_NULLS_FIELDS">FI: Finalizer nulls fields</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#FI_FINALIZER_ONLY_NULLS_FIELDS">FI: Finalizer only nulls fields</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#FI_MISSING_SUPER_CALL">FI: Finalizer does not call superclass finalizer</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#FI_NULLIFY_SUPER">FI: Finalizer nullifies superclass finalizer</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#FI_USELESS">FI: Finalizer does nothing but call superclass finalizer</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_FORMAT_STRING_USES_NEWLINE">FS: Format string should use %n rather than \n</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#GC_UNCHECKED_TYPE_IN_GENERIC_CALL">GC: Unchecked type in generic call</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#HE_EQUALS_NO_HASHCODE">HE: Class defines equals() but not hashCode()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#HE_EQUALS_USE_HASHCODE">HE: Class defines equals() and uses Object.hashCode()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#HE_HASHCODE_NO_EQUALS">HE: Class defines hashCode() but not equals()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#HE_HASHCODE_USE_OBJECT_EQUALS">HE: Class defines hashCode() and uses Object.equals()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#HE_INHERITS_EQUALS_USE_HASHCODE">HE: Class inherits equals() and uses Object.hashCode()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION">IC: Superclass uses subclass during initialization</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IMSE_DONT_CATCH_IMSE">IMSE: Dubious catching of IllegalMonitorStateException</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ISC_INSTANTIATE_STATIC_CLASS">ISC: Needless instantiation of class that only supplies static methods</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IT_NO_SUCH_ELEMENT">It: Iterator next() method can't throw NoSuchElementException</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#J2EE_STORE_OF_NON_SERIALIZABLE_OBJECT_INTO_SESSION">J2EE: Store of non serializable object into HttpSession</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#JCIP_FIELD_ISNT_FINAL_IN_IMMUTABLE_CLASS">JCIP: Fields of immutable classes should be final</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_BOOLEAN_RETURN_NULL">NP: Method with Boolean return type returns explicit null</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_CLONE_COULD_RETURN_NULL">NP: Clone method may return null</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_EQUALS_SHOULD_HANDLE_NULL_ARGUMENT">NP: equals() method does not check for null argument</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_TOSTRING_COULD_RETURN_NULL">NP: toString method may return null</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_CLASS_NAMING_CONVENTION">Nm: Class names should start with an upper case letter</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_CLASS_NOT_EXCEPTION">Nm: Class is not derived from an Exception, even though it is named as such</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_CONFUSING">Nm: Confusing method names</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_FIELD_NAMING_CONVENTION">Nm: Field names should start with a lower case letter</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_FUTURE_KEYWORD_USED_AS_IDENTIFIER">Nm: Use of identifier that is a keyword in later versions of Java</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_FUTURE_KEYWORD_USED_AS_MEMBER_IDENTIFIER">Nm: Use of identifier that is a keyword in later versions of Java</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_METHOD_NAMING_CONVENTION">Nm: Method names should start with a lower case letter</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_SAME_SIMPLE_NAME_AS_INTERFACE">Nm: Class names shouldn't shadow simple name of implemented interface</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_SAME_SIMPLE_NAME_AS_SUPERCLASS">Nm: Class names shouldn't shadow simple name of superclass</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_VERY_CONFUSING_INTENTIONAL">Nm: Very confusing method names (but perhaps intentional)</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_WRONG_PACKAGE_INTENTIONAL">Nm: Method doesn't override method in superclass due to wrong package for parameter</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ODR_OPEN_DATABASE_RESOURCE">ODR: Method may fail to close database resource</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ODR_OPEN_DATABASE_RESOURCE_EXCEPTION_PATH">ODR: Method may fail to close database resource on exception</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#OS_OPEN_STREAM">OS: Method may fail to close stream</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#OS_OPEN_STREAM_EXCEPTION_PATH">OS: Method may fail to close stream on exception</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#PZ_DONT_REUSE_ENTRY_OBJECTS_IN_ITERATORS">PZ: Don't reuse entry objects in iterators</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RC_REF_COMPARISON_BAD_PRACTICE">RC: Suspicious reference comparison to constant</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RC_REF_COMPARISON_BAD_PRACTICE_BOOLEAN">RC: Suspicious reference comparison of Boolean values</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RR_NOT_CHECKED">RR: Method ignores results of InputStream.read()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SR_NOT_CHECKED">RR: Method ignores results of InputStream.skip()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_NEGATING_RESULT_OF_COMPARETO">RV: Negating the result of compareTo()/compare()</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_RETURN_VALUE_IGNORED_BAD_PRACTICE">RV: Method ignores exceptional return value</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SI_INSTANCE_BEFORE_FINALS_ASSIGNED">SI: Static initializer creates instance before all static final fields assigned</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SW_SWING_METHODS_INVOKED_IN_SWING_THREAD">SW: Certain swing methods needs to be invoked in Swing thread</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_BAD_FIELD">Se: Non-transient non-serializable instance field in serializable class</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_BAD_FIELD_INNER_CLASS">Se: Non-serializable class has a serializable inner class</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_BAD_FIELD_STORE">Se: Non-serializable value stored into instance field of a serializable class</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_COMPARATOR_SHOULD_BE_SERIALIZABLE">Se: Comparator doesn't implement Serializable</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_INNER_CLASS">Se: Serializable inner class</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_NONFINAL_SERIALVERSIONID">Se: serialVersionUID isn't final</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_NONLONG_SERIALVERSIONID">Se: serialVersionUID isn't long</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_NONSTATIC_SERIALVERSIONID">Se: serialVersionUID isn't static</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_NO_SUITABLE_CONSTRUCTOR">Se: Class is Serializable but its superclass doesn't define a void constructor</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_NO_SUITABLE_CONSTRUCTOR_FOR_EXTERNALIZATION">Se: Class is Externalizable but doesn't define a void constructor</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_READ_RESOLVE_MUST_RETURN_OBJECT">Se: The readResolve method must be declared with a return type of Object. </a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_TRANSIENT_FIELD_NOT_RESTORED">Se: Transient field that isn't set by deserialization. </a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_NO_SERIALVERSIONID">SnVI: Class is Serializable, but doesn't define serialVersionUID</a></td><td>Bad practice</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UI_INHERITANCE_UNSAFE_GETRESOURCE">UI: Usage of GetResource may be unsafe if class is extended</a></td><td>Bad practice</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BC_IMPOSSIBLE_CAST">BC: Impossible cast</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_IMPOSSIBLE_DOWNCAST">BC: Impossible downcast</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BC_IMPOSSIBLE_DOWNCAST_OF_TOARRAY">BC: Impossible downcast of toArray() result</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_IMPOSSIBLE_INSTANCEOF">BC: instanceof will always return false</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BIT_ADD_OF_SIGNED_BYTE">BIT: Bitwise add of signed byte value</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BIT_AND">BIT: Incompatible bit masks</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BIT_AND_ZZ">BIT: Check to see if ((...) & 0) == 0</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BIT_IOR">BIT: Incompatible bit masks</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BIT_IOR_OF_SIGNED_BYTE">BIT: Bitwise OR of signed byte value</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BIT_SIGNED_CHECK_HIGH_BIT">BIT: Check for sign of bitwise operation</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BOA_BADLY_OVERRIDDEN_ADAPTER">BOA: Class overrides a method implemented in super class Adapter wrongly</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ICAST_BAD_SHIFT_AMOUNT">BSHIFT: 32 bit int shifted by an amount not in the range 0..31</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BX_UNBOXED_AND_COERCED_FOR_TERNARY_OPERATOR">Bx: Primitive value is unboxed and coerced for ternary operator</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#CO_COMPARETO_RESULTS_MIN_VALUE">Co: compareTo()/compare() returns Integer.MIN_VALUE</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DLS_DEAD_STORE_OF_CLASS_LITERAL">DLS: Dead store of class literal</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DLS_OVERWRITTEN_INCREMENT">DLS: Overwritten increment</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_ARGUMENTS_WRONG_ORDER">DMI: Reversed method arguments</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_BAD_MONTH">DMI: Bad constant value for month</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_BIGDECIMAL_CONSTRUCTED_FROM_DOUBLE">DMI: BigDecimal constructed from double that isn't represented precisely</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_CALLING_NEXT_FROM_HASNEXT">DMI: hasNext method invokes next</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_COLLECTIONS_SHOULD_NOT_CONTAIN_THEMSELVES">DMI: Collections should not contain themselves</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_DOH">DMI: D'oh! A nonsensical method invocation</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_INVOKING_HASHCODE_ON_ARRAY">DMI: Invocation of hashCode on an array</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_LONG_BITS_TO_DOUBLE_INVOKED_ON_INT">DMI: Double.longBitsToDouble invoked on an int</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_VACUOUS_SELF_COLLECTION_CALL">DMI: Vacuous call to collections</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_ANNOTATION_IS_NOT_VISIBLE_TO_REFLECTION">Dm: Can't use reflection to check for presence of annotation without runtime retention</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_FUTILE_ATTEMPT_TO_CHANGE_MAXPOOL_SIZE_OF_SCHEDULED_THREAD_POOL_EXECUTOR">Dm: Futile attempt to change max pool size of ScheduledThreadPoolExecutor</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_SCHEDULED_THREAD_POOL_EXECUTOR_WITH_ZERO_CORE_THREADS">Dm: Creation of ScheduledThreadPoolExecutor with zero core threads</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_VACUOUS_CALL_TO_EASYMOCK_METHOD">Dm: Useless/vacuous call to EasyMock method</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EC_ARRAY_AND_NONARRAY">EC: equals() used to compare array and nonarray</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EC_BAD_ARRAY_COMPARE">EC: Invocation of equals() on an array, which is equivalent to ==</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EC_INCOMPATIBLE_ARRAY_COMPARE">EC: equals(...) used to compare incompatible arrays</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EC_NULL_ARG">EC: Call to equals(null)</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EC_UNRELATED_CLASS_AND_INTERFACE">EC: Call to equals() comparing unrelated class and interface</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EC_UNRELATED_INTERFACES">EC: Call to equals() comparing different interface types</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EC_UNRELATED_TYPES">EC: Call to equals() comparing different types</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EC_UNRELATED_TYPES_USING_POINTER_EQUALITY">EC: Using pointer equality to compare different types</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_ALWAYS_FALSE">Eq: equals method always returns false</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_ALWAYS_TRUE">Eq: equals method always returns true</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_COMPARING_CLASS_NAMES">Eq: equals method compares class names rather than class objects</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_DONT_DEFINE_EQUALS_FOR_ENUM">Eq: Covariant equals() method defined for enum</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_OTHER_NO_OBJECT">Eq: equals() method defined that doesn't override equals(Object)</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_OTHER_USE_OBJECT">Eq: equals() method defined that doesn't override Object.equals(Object)</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_OVERRIDING_EQUALS_NOT_SYMMETRIC">Eq: equals method overrides equals in superclass and may not be symmetric</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_SELF_USE_OBJECT">Eq: Covariant equals() method defined, Object.equals(Object) inherited</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#FE_TEST_IF_EQUAL_TO_NOT_A_NUMBER">FE: Doomed test for equality to NaN</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VA_FORMAT_STRING_BAD_ARGUMENT">FS: Format string placeholder incompatible with passed argument</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_FORMAT_STRING_BAD_CONVERSION">FS: The type of a supplied argument doesn't match format specifier</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VA_FORMAT_STRING_EXPECTED_MESSAGE_FORMAT_SUPPLIED">FS: MessageFormat supplied where printf style format expected</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_FORMAT_STRING_EXTRA_ARGUMENTS_PASSED">FS: More arguments are passed than are actually used in the format string</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VA_FORMAT_STRING_ILLEGAL">FS: Illegal format string</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_FORMAT_STRING_MISSING_ARGUMENT">FS: Format string references missing argument</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VA_FORMAT_STRING_NO_PREVIOUS_ARGUMENT">FS: No previous argument for format string</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#GC_UNRELATED_TYPES">GC: No relationship between generic parameter and method argument</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#HE_SIGNATURE_DECLARES_HASHING_OF_UNHASHABLE_CLASS">HE: Signature declares use of unhashable class in hashed construct</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#HE_USE_OF_UNHASHABLE_CLASS">HE: Use of class without a hashCode() method in a hashed data structure</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ICAST_INT_2_LONG_AS_INSTANT">ICAST: int value converted to long and used as absolute time</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ICAST_INT_CAST_TO_DOUBLE_PASSED_TO_CEIL">ICAST: integral value cast to double and then passed to Math.ceil</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ICAST_INT_CAST_TO_FLOAT_PASSED_TO_ROUND">ICAST: int value cast to float and then passed to Math.round</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IJU_ASSERT_METHOD_INVOKED_FROM_RUN_METHOD">IJU: JUnit assertion in run method will not be noticed by JUnit</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IJU_BAD_SUITE_METHOD">IJU: TestCase declares a bad suite method </a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IJU_NO_TESTS">IJU: TestCase has no tests</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IJU_SETUP_NO_SUPER">IJU: TestCase defines setUp that doesn't call super.setUp()</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IJU_SUITE_NOT_STATIC">IJU: TestCase implements a non-static suite method </a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IJU_TEARDOWN_NO_SUPER">IJU: TestCase defines tearDown that doesn't call super.tearDown()</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IL_CONTAINER_ADDED_TO_ITSELF">IL: A collection is added to itself</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IL_INFINITE_LOOP">IL: An apparent infinite loop</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IL_INFINITE_RECURSIVE_LOOP">IL: An apparent infinite recursive loop</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IM_MULTIPLYING_RESULT_OF_IREM">IM: Integer multiply of result of integer remainder</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#INT_BAD_COMPARISON_WITH_INT_VALUE">INT: Bad comparison of int value with long constant</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#INT_BAD_COMPARISON_WITH_NONNEGATIVE_VALUE">INT: Bad comparison of nonnegative value with negative constant</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#INT_BAD_COMPARISON_WITH_SIGNED_BYTE">INT: Bad comparison of signed byte</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IO_APPENDING_TO_OBJECT_OUTPUT_STREAM">IO: Doomed attempt to append to an object output stream</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IP_PARAMETER_IS_DEAD_BUT_OVERWRITTEN">IP: A parameter is dead upon entry to a method but overwritten</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MF_CLASS_MASKS_FIELD">MF: Class defines field that masks a superclass field</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MF_METHOD_MASKS_FIELD">MF: Method defines a variable that obscures a field</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_ALWAYS_NULL">NP: Null pointer dereference</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_ALWAYS_NULL_EXCEPTION">NP: Null pointer dereference in method on exception path</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_ARGUMENT_MIGHT_BE_NULL">NP: Method does not check for null argument</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_CLOSING_NULL">NP: close() invoked on a value that is always null</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_GUARANTEED_DEREF">NP: Null value is guaranteed to be dereferenced</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_GUARANTEED_DEREF_ON_EXCEPTION_PATH">NP: Value is null and guaranteed to be dereferenced on exception path</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NONNULL_FIELD_NOT_INITIALIZED_IN_CONSTRUCTOR">NP: Nonnull field is not initialized</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_NONNULL_PARAM_VIOLATION">NP: Method call passes null to a nonnull parameter </a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NONNULL_RETURN_VIOLATION">NP: Method may return null, but is declared @NonNull</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_NULL_INSTANCEOF">NP: A known null value is checked to see if it is an instance of a type</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NULL_ON_SOME_PATH">NP: Possible null pointer dereference</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_NULL_ON_SOME_PATH_EXCEPTION">NP: Possible null pointer dereference in method on exception path</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NULL_PARAM_DEREF">NP: Method call passes null for nonnull parameter</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_NULL_PARAM_DEREF_ALL_TARGETS_DANGEROUS">NP: Method call passes null for nonnull parameter</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NULL_PARAM_DEREF_NONVIRTUAL">NP: Non-virtual method call passes null for nonnull parameter</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_STORE_INTO_NONNULL_FIELD">NP: Store of null value into field annotated NonNull</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_UNWRITTEN_FIELD">NP: Read of unwritten field</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_BAD_EQUAL">Nm: Class defines equal(Object); should it be equals(Object)?</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_LCASE_HASHCODE">Nm: Class defines hashcode(); should it be hashCode()?</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_LCASE_TOSTRING">Nm: Class defines tostring(); should it be toString()?</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_METHOD_CONSTRUCTOR_CONFUSION">Nm: Apparent method/constructor confusion</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NM_VERY_CONFUSING">Nm: Very confusing method names</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NM_WRONG_PACKAGE">Nm: Method doesn't override method in superclass due to wrong package for parameter</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#QBA_QUESTIONABLE_BOOLEAN_ASSIGNMENT">QBA: Method assigns boolean literal in boolean expression</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RC_REF_COMPARISON">RC: Suspicious reference comparison</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RCN_REDUNDANT_NULLCHECK_WOULD_HAVE_BEEN_A_NPE">RCN: Nullcheck of value previously dereferenced</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RE_BAD_SYNTAX_FOR_REGULAR_EXPRESSION">RE: Invalid syntax for regular expression</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RE_CANT_USE_FILE_SEPARATOR_AS_REGULAR_EXPRESSION">RE: File.separator used for regular expression</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RE_POSSIBLE_UNINTENDED_PATTERN">RE: "." used for regular expression</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_01_TO_INT">RV: Random value from 0 to 1 is coerced to the integer 0</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_ABSOLUTE_VALUE_OF_HASHCODE">RV: Bad attempt to compute absolute value of signed 32-bit hashcode </a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_ABSOLUTE_VALUE_OF_RANDOM_INT">RV: Bad attempt to compute absolute value of signed random integer</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_CHECK_COMPARETO_FOR_SPECIFIC_RETURN_VALUE">RV: Code checks for specific values returned by compareTo</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_EXCEPTION_NOT_THROWN">RV: Exception created and dropped rather than thrown</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_RETURN_VALUE_IGNORED">RV: Method ignores return value</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RpC_REPEATED_CONDITIONAL_TEST">RpC: Repeated conditional tests</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SA_FIELD_SELF_ASSIGNMENT">SA: Self assignment of field</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SA_FIELD_SELF_COMPARISON">SA: Self comparison of field with itself</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SA_FIELD_SELF_COMPUTATION">SA: Nonsensical self computation involving a field (e.g., x & x)</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SA_LOCAL_SELF_ASSIGNMENT_INSTEAD_OF_FIELD">SA: Self assignment of local rather than assignment to field</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SA_LOCAL_SELF_COMPARISON">SA: Self comparison of value with itself</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SA_LOCAL_SELF_COMPUTATION">SA: Nonsensical self computation involving a variable (e.g., x & x)</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SF_DEAD_STORE_DUE_TO_SWITCH_FALLTHROUGH">SF: Dead store due to switch statement fall through</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SF_DEAD_STORE_DUE_TO_SWITCH_FALLTHROUGH_TO_THROW">SF: Dead store due to switch statement fall through to throw</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SIC_THREADLOCAL_DEADLY_EMBRACE">SIC: Deadly embrace of non-static inner class and thread local</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SIO_SUPERFLUOUS_INSTANCEOF">SIO: Unnecessary type check done using instanceof operator</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SQL_BAD_PREPARED_STATEMENT_ACCESS">SQL: Method attempts to access a prepared statement parameter with index 0</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SQL_BAD_RESULTSET_ACCESS">SQL: Method attempts to access a result set field with index 0</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#STI_INTERRUPTED_ON_CURRENTTHREAD">STI: Unneeded use of currentThread() call, to call interrupted() </a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#STI_INTERRUPTED_ON_UNKNOWNTHREAD">STI: Static Thread.interrupted() method invoked on thread instance</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_METHOD_MUST_BE_PRIVATE">Se: Method must be private in order for serialization to work</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_READ_RESOLVE_IS_STATIC">Se: The readResolve method must not be declared as a static method. </a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#TQ_ALWAYS_VALUE_USED_WHERE_NEVER_REQUIRED">TQ: Value annotated as carrying a type qualifier used where a value that must not carry that qualifier is required</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#TQ_COMPARING_VALUES_WITH_INCOMPATIBLE_TYPE_QUALIFIERS">TQ: Comparing values with incompatible type qualifiers</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#TQ_MAYBE_SOURCE_VALUE_REACHES_ALWAYS_SINK">TQ: Value that might not carry a type qualifier is always used in a way requires that type qualifier</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#TQ_MAYBE_SOURCE_VALUE_REACHES_NEVER_SINK">TQ: Value that might carry a type qualifier is always used in a way prohibits it from having that type qualifier</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#TQ_NEVER_VALUE_USED_WHERE_ALWAYS_REQUIRED">TQ: Value annotated as never carrying a type qualifier used where value carrying that qualifier is required</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UMAC_UNCALLABLE_METHOD_OF_ANONYMOUS_CLASS">UMAC: Uncallable method defined in anonymous class</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UR_UNINIT_READ">UR: Uninitialized read of field in constructor</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UR_UNINIT_READ_CALLED_FROM_SUPER_CONSTRUCTOR">UR: Uninitialized read of field method called from constructor of superclass</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_INVOKING_TOSTRING_ON_ANONYMOUS_ARRAY">USELESS_STRING: Invocation of toString on an array</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_INVOKING_TOSTRING_ON_ARRAY">USELESS_STRING: Invocation of toString on an array</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VA_FORMAT_STRING_BAD_CONVERSION_FROM_ARRAY">USELESS_STRING: Array formatted in useless way using format string</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UWF_NULL_FIELD">UwF: Field only ever set to null</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UWF_UNWRITTEN_FIELD">UwF: Unwritten field</a></td><td>Correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_PRIMITIVE_ARRAY_PASSED_TO_OBJECT_VARARG">VA: Primitive array passed to function expecting a variable number of object arguments</a></td><td>Correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#LG_LOST_LOGGER_DUE_TO_WEAK_REFERENCE">LG: Potential lost logger changes due to weak reference in OpenJDK</a></td><td>Experimental</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#OBL_UNSATISFIED_OBLIGATION">OBL: Method may fail to clean up stream or resource</a></td><td>Experimental</td></tr>
<tr bgcolor="#ffffff"><td><a href="#OBL_UNSATISFIED_OBLIGATION_EXCEPTION_EDGE">OBL: Method may fail to clean up stream or resource on checked exception</a></td><td>Experimental</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_CONVERT_CASE">Dm: Consider using Locale parameterized version of invoked method</a></td><td>Internationalization</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_DEFAULT_ENCODING">Dm: Reliance on default encoding</a></td><td>Internationalization</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DP_CREATE_CLASSLOADER_INSIDE_DO_PRIVILEGED">DP: Classloaders should only be created inside doPrivileged block</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DP_DO_INSIDE_DO_PRIVILEGED">DP: Method invoked that should be only be invoked inside a doPrivileged block</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EI_EXPOSE_REP">EI: May expose internal representation by returning reference to mutable object</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EI_EXPOSE_REP2">EI2: May expose internal representation by incorporating reference to mutable object</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#FI_PUBLIC_SHOULD_BE_PROTECTED">FI: Finalizer should be protected, not public</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EI_EXPOSE_STATIC_REP2">MS: May expose internal static state by storing a mutable object into a static field</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MS_CANNOT_BE_FINAL">MS: Field isn't final and can't be protected from malicious code</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MS_EXPOSE_REP">MS: Public static method may expose internal representation by returning array</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MS_FINAL_PKGPROTECT">MS: Field should be both final and package protected</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MS_MUTABLE_ARRAY">MS: Field is a mutable array</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MS_MUTABLE_HASHTABLE">MS: Field is a mutable Hashtable</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MS_OOI_PKGPROTECT">MS: Field should be moved out of an interface and made package protected</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MS_PKGPROTECT">MS: Field should be package protected</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MS_SHOULD_BE_FINAL">MS: Field isn't final but should be</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MS_SHOULD_BE_REFACTORED_TO_BE_FINAL">MS: Field isn't final but should be refactored to be so</a></td><td>Malicious code vulnerability</td></tr>
<tr bgcolor="#ffffff"><td><a href="#AT_OPERATION_SEQUENCE_ON_CONCURRENT_ABSTRACTION">AT: Sequence of calls to concurrent abstraction may not be atomic</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DC_DOUBLECHECK">DC: Possible double check of field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DL_SYNCHRONIZATION_ON_BOOLEAN">DL: Synchronization on Boolean</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DL_SYNCHRONIZATION_ON_BOXED_PRIMITIVE">DL: Synchronization on boxed primitive</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DL_SYNCHRONIZATION_ON_SHARED_CONSTANT">DL: Synchronization on interned String </a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DL_SYNCHRONIZATION_ON_UNSHARED_BOXED_PRIMITIVE">DL: Synchronization on boxed primitive values</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_MONITOR_WAIT_ON_CONDITION">Dm: Monitor wait() called on Condition</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_USELESS_THREAD">Dm: A thread was created using the default empty run method</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ESync_EMPTY_SYNC">ESync: Empty synchronized block</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IS2_INCONSISTENT_SYNC">IS: Inconsistent synchronization</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IS_FIELD_NOT_GUARDED">IS: Field not guarded against concurrent access</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#JLM_JSR166_LOCK_MONITORENTER">JLM: Synchronization performed on Lock</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#JLM_JSR166_UTILCONCURRENT_MONITORENTER">JLM: Synchronization performed on util.concurrent instance</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#JML_JSR166_CALLING_WAIT_RATHER_THAN_AWAIT">JLM: Using monitor style wait methods on util.concurrent abstraction</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#LI_LAZY_INIT_STATIC">LI: Incorrect lazy initialization of static field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#LI_LAZY_INIT_UPDATE_STATIC">LI: Incorrect lazy initialization and update of static field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ML_SYNC_ON_FIELD_TO_GUARD_CHANGING_THAT_FIELD">ML: Synchronization on field in futile attempt to guard that field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ML_SYNC_ON_UPDATED_FIELD">ML: Method synchronizes on an updated field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MSF_MUTABLE_SERVLET_FIELD">MSF: Mutable servlet field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MWN_MISMATCHED_NOTIFY">MWN: Mismatched notify()</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MWN_MISMATCHED_WAIT">MWN: Mismatched wait()</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NN_NAKED_NOTIFY">NN: Naked notify</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_SYNC_AND_NULL_CHECK_FIELD">NP: Synchronize and null check on the same field.</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NO_NOTIFY_NOT_NOTIFYALL">No: Using notify() rather than notifyAll()</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RS_READOBJECT_SYNC">RS: Class's readObject() method is synchronized</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_RETURN_VALUE_OF_PUTIFABSENT_IGNORED">RV: Return value of putIfAbsent ignored, value passed to putIfAbsent reused</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RU_INVOKE_RUN">Ru: Invokes run on a thread (did you mean to start it instead?)</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SC_START_IN_CTOR">SC: Constructor invokes Thread.start()</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SP_SPIN_ON_FIELD">SP: Method spins on field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#STCAL_INVOKE_ON_STATIC_CALENDAR_INSTANCE">STCAL: Call to static Calendar</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#STCAL_INVOKE_ON_STATIC_DATE_FORMAT_INSTANCE">STCAL: Call to static DateFormat</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#STCAL_STATIC_CALENDAR_INSTANCE">STCAL: Static Calendar field</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#STCAL_STATIC_SIMPLE_DATE_FORMAT_INSTANCE">STCAL: Static DateFormat</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SWL_SLEEP_WITH_LOCK_HELD">SWL: Method calls Thread.sleep() with a lock held</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#TLW_TWO_LOCK_WAIT">TLW: Wait with two locks held</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UG_SYNC_SET_UNSYNC_GET">UG: Unsynchronized get method, synchronized set method</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UL_UNRELEASED_LOCK">UL: Method does not release lock on all paths</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UL_UNRELEASED_LOCK_EXCEPTION_PATH">UL: Method does not release lock on all exception paths</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UW_UNCOND_WAIT">UW: Unconditional wait</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VO_VOLATILE_INCREMENT">VO: An increment to a volatile field isn't atomic</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#VO_VOLATILE_REFERENCE_TO_ARRAY">VO: A volatile reference to an array doesn't treat the array elements as volatile</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#WL_USING_GETCLASS_RATHER_THAN_CLASS_LITERAL">WL: Synchronization on getClass rather than class literal</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#WS_WRITEOBJECT_SYNC">WS: Class's writeObject() method is synchronized but nothing else is</a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#WA_AWAIT_NOT_IN_LOOP">Wa: Condition.await() not in loop </a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#ffffff"><td><a href="#WA_NOT_IN_LOOP">Wa: Wait not in loop </a></td><td>Multithreaded correctness</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BX_BOXING_IMMEDIATELY_UNBOXED">Bx: Primitive value is boxed and then immediately unboxed</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BX_BOXING_IMMEDIATELY_UNBOXED_TO_PERFORM_COERCION">Bx: Primitive value is boxed then unboxed to perform primitive coercion</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BX_UNBOXING_IMMEDIATELY_REBOXED">Bx: Boxed value is unboxed and then immediately reboxed</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_BOXED_PRIMITIVE_TOSTRING">Bx: Method allocates a boxed primitive just to call toString</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_FP_NUMBER_CTOR">Bx: Method invokes inefficient floating-point Number constructor; use static valueOf instead</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_NUMBER_CTOR">Bx: Method invokes inefficient Number constructor; use static valueOf instead</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_BLOCKING_METHODS_ON_URL">Dm: The equals and hashCode methods of URL are blocking</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_COLLECTION_OF_URLS">Dm: Maps and sets of URLs can be performance hogs</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_BOOLEAN_CTOR">Dm: Method invokes inefficient Boolean constructor; use Boolean.valueOf(...) instead</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_GC">Dm: Explicit garbage collection; extremely dubious except in benchmarking code</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_NEW_FOR_GETCLASS">Dm: Method allocates an object, only to get the class object</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_NEXTINT_VIA_NEXTDOUBLE">Dm: Use the nextInt method of Random rather than nextDouble to generate a random integer</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_STRING_CTOR">Dm: Method invokes inefficient new String(String) constructor</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DM_STRING_TOSTRING">Dm: Method invokes toString() method on a String</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DM_STRING_VOID_CTOR">Dm: Method invokes inefficient new String() constructor</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#HSC_HUGE_SHARED_STRING_CONSTANT">HSC: Huge string constants is duplicated across multiple class files</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ITA_INEFFICIENT_TO_ARRAY">ITA: Method uses toArray() with zero-length array argument</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SBSC_USE_STRINGBUFFER_CONCATENATION">SBSC: Method concatenates strings using + in a loop</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SIC_INNER_SHOULD_BE_STATIC">SIC: Should be a static inner class</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SIC_INNER_SHOULD_BE_STATIC_ANON">SIC: Could be refactored into a named static inner class</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SIC_INNER_SHOULD_BE_STATIC_NEEDS_THIS">SIC: Could be refactored into a static inner class</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SS_SHOULD_BE_STATIC">SS: Unread field: should this field be static?</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UM_UNNECESSARY_MATH">UM: Method calls static Math class method on a constant value</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UPM_UNCALLED_PRIVATE_METHOD">UPM: Private method is never called</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#URF_UNREAD_FIELD">UrF: Unread field</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UUF_UNUSED_FIELD">UuF: Unused field</a></td><td>Performance</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#WMI_WRONG_MAP_ITERATOR">WMI: Inefficient use of keySet iterator instead of entrySet iterator</a></td><td>Performance</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_CONSTANT_DB_PASSWORD">Dm: Hardcoded constant database password</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_EMPTY_DB_PASSWORD">Dm: Empty database password</a></td><td>Security</td></tr>
<tr bgcolor="#ffffff"><td><a href="#HRS_REQUEST_PARAMETER_TO_COOKIE">HRS: HTTP cookie formed from untrusted input</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#HRS_REQUEST_PARAMETER_TO_HTTP_HEADER">HRS: HTTP Response splitting vulnerability</a></td><td>Security</td></tr>
<tr bgcolor="#ffffff"><td><a href="#PT_ABSOLUTE_PATH_TRAVERSAL">PT: Absolute path traversal in servlet</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#PT_RELATIVE_PATH_TRAVERSAL">PT: Relative path traversal in servlet</a></td><td>Security</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SQL_NONCONSTANT_STRING_PASSED_TO_EXECUTE">SQL: Nonconstant string passed to execute method on an SQL statement</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SQL_PREPARED_STATEMENT_GENERATED_FROM_NONCONSTANT_STRING">SQL: A prepared statement is generated from a nonconstant String</a></td><td>Security</td></tr>
<tr bgcolor="#ffffff"><td><a href="#XSS_REQUEST_PARAMETER_TO_JSP_WRITER">XSS: JSP reflected cross site scripting vulnerability</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#XSS_REQUEST_PARAMETER_TO_SEND_ERROR">XSS: Servlet reflected cross site scripting vulnerability in error page</a></td><td>Security</td></tr>
<tr bgcolor="#ffffff"><td><a href="#XSS_REQUEST_PARAMETER_TO_SERVLET_WRITER">XSS: Servlet reflected cross site scripting vulnerability</a></td><td>Security</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_BAD_CAST_TO_ABSTRACT_COLLECTION">BC: Questionable cast to abstract collection </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BC_BAD_CAST_TO_CONCRETE_COLLECTION">BC: Questionable cast to concrete collection</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_UNCONFIRMED_CAST">BC: Unchecked/unconfirmed cast</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#BC_UNCONFIRMED_CAST_OF_RETURN_VALUE">BC: Unchecked/unconfirmed cast of return value from method</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#BC_VACUOUS_INSTANCEOF">BC: instanceof will always return true</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ICAST_QUESTIONABLE_UNSIGNED_RIGHT_SHIFT">BSHIFT: Unsigned right shift cast to short/byte</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#CI_CONFUSED_INHERITANCE">CI: Class is final but declares protected field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DB_DUPLICATE_BRANCHES">DB: Method uses the same code for two branches</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DB_DUPLICATE_SWITCH_CLAUSES">DB: Method uses the same code for two switch clauses</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DLS_DEAD_LOCAL_STORE">DLS: Dead store to local variable</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DLS_DEAD_LOCAL_STORE_IN_RETURN">DLS: Useless assignment in return statement</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DLS_DEAD_LOCAL_STORE_OF_NULL">DLS: Dead store of null to local variable</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DLS_DEAD_LOCAL_STORE_SHADOWS_FIELD">DLS: Dead store to local variable that shadows field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_HARDCODED_ABSOLUTE_FILENAME">DMI: Code contains a hard coded reference to an absolute pathname</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_NONSERIALIZABLE_OBJECT_WRITTEN">DMI: Non serializable object written to ObjectOutput</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#DMI_USELESS_SUBSTRING">DMI: Invocation of substring(0), which returns the original value</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#DMI_THREAD_PASSED_WHERE_RUNNABLE_EXPECTED">Dm: Thread passed where Runnable expected</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#EQ_DOESNT_OVERRIDE_EQUALS">Eq: Class doesn't override equals in superclass</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#EQ_UNUSUAL">Eq: Unusual equals method </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#FE_FLOATING_POINT_EQUALITY">FE: Test for floating point equality</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#VA_FORMAT_STRING_BAD_CONVERSION_TO_BOOLEAN">FS: Non-Boolean argument formatted using %b format specifier</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IA_AMBIGUOUS_INVOCATION_OF_INHERITED_OR_OUTER_METHOD">IA: Ambiguous invocation of either an inherited or outer method</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IC_INIT_CIRCULARITY">IC: Initialization circularity</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ICAST_IDIV_CAST_TO_DOUBLE">ICAST: integral division result cast to double or float</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#ICAST_INTEGER_MULTIPLY_CAST_TO_LONG">ICAST: Result of integer multiplication cast to long</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#IM_AVERAGE_COMPUTATION_COULD_OVERFLOW">IM: Computation of average could overflow</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#IM_BAD_CHECK_FOR_ODD">IM: Check for oddness that won't work for negative numbers </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#INT_BAD_REM_BY_1">INT: Integer remainder modulo 1</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#INT_VACUOUS_BIT_OPERATION">INT: Vacuous bit mask operation on integer value</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#INT_VACUOUS_COMPARISON">INT: Vacuous comparison of integer value</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#MTIA_SUSPECT_SERVLET_INSTANCE_FIELD">MTIA: Class extends Servlet class and uses instance variables</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#MTIA_SUSPECT_STRUTS_INSTANCE_FIELD">MTIA: Class extends Struts Action class and uses instance variables</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_DEREFERENCE_OF_READLINE_VALUE">NP: Dereference of the result of readLine() without nullcheck</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_IMMEDIATE_DEREFERENCE_OF_READLINE">NP: Immediate dereference of the result of readLine()</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_LOAD_OF_KNOWN_NULL_VALUE">NP: Load of known null value</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE">NP: Possible null pointer dereference due to return value of called method</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_NULL_ON_SOME_PATH_MIGHT_BE_INFEASIBLE">NP: Possible null pointer dereference on branch that might be infeasible</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE">NP: Parameter must be nonnull but is marked as nullable</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NP_UNWRITTEN_PUBLIC_OR_PROTECTED_FIELD">NP: Read of unwritten public or protected field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#NS_DANGEROUS_NON_SHORT_CIRCUIT">NS: Potentially dangerous use of non-short-circuit logic</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#NS_NON_SHORT_CIRCUIT">NS: Questionable use of non-short-circuit logic</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#PZLA_PREFER_ZERO_LENGTH_ARRAYS">PZLA: Consider returning a zero length array rather than null</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#QF_QUESTIONABLE_FOR_LOOP">QF: Complicated, subtle or wrong increment in for-loop </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RCN_REDUNDANT_COMPARISON_OF_NULL_AND_NONNULL_VALUE">RCN: Redundant comparison of non-null value to null</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RCN_REDUNDANT_COMPARISON_TWO_NULL_VALUES">RCN: Redundant comparison of two null values</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE">RCN: Redundant nullcheck of value known to be non-null</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE">RCN: Redundant nullcheck of value known to be null</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#REC_CATCH_EXCEPTION">REC: Exception is caught when Exception is not thrown</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RI_REDUNDANT_INTERFACES">RI: Class implements same interface as superclass</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_CHECK_FOR_POSITIVE_INDEXOF">RV: Method checks to see if result of String.indexOf is positive</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_DONT_JUST_NULL_CHECK_READLINE">RV: Method discards result of readLine after checking if it is nonnull</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_REM_OF_HASHCODE">RV: Remainder of hashCode could be negative</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#RV_REM_OF_RANDOM_INT">RV: Remainder of 32-bit signed random integer</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#RV_RETURN_VALUE_IGNORED_INFERRED">RV: Method ignores return value, is this OK?</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SA_FIELD_DOUBLE_ASSIGNMENT">SA: Double assignment of field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SA_LOCAL_DOUBLE_ASSIGNMENT">SA: Double assignment of local variable </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SA_LOCAL_SELF_ASSIGNMENT">SA: Self assignment of local variable</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SF_SWITCH_FALLTHROUGH">SF: Switch statement found where one case falls through to the next case</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SF_SWITCH_NO_DEFAULT">SF: Switch statement found where default case is missing</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD">ST: Write to static field from instance method</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#SE_PRIVATE_READ_RESOLVE_NOT_INHERITED">Se: private readResolve method not inherited by subclasses</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#SE_TRANSIENT_FIELD_OF_NONSERIALIZABLE_CLASS">Se: Transient field of class that isn't Serializable. </a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_ALWAYS_SINK">TQ: Value required to have type qualifier, but marked as unknown</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#TQ_EXPLICIT_UNKNOWN_SOURCE_VALUE_REACHES_NEVER_SINK">TQ: Value required to not have type qualifier, but marked as unknown</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UCF_USELESS_CONTROL_FLOW">UCF: Useless control flow</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UCF_USELESS_CONTROL_FLOW_NEXT_LINE">UCF: Useless control flow to next line</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD">UrF: Unread public/protected field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD">UuF: Unused public or protected field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#UWF_FIELD_NOT_INITIALIZED_IN_CONSTRUCTOR">UwF: Field not initialized in constructor but dereferenced without null check</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#ffffff"><td><a href="#UWF_UNWRITTEN_PUBLIC_OR_PROTECTED_FIELD">UwF: Unwritten public or protected field</a></td><td>Dodgy code</td></tr>
<tr bgcolor="#eeeeee"><td><a href="#XFB_XML_FACTORY_BYPASS">XFB: Method directly allocates a specific implementation of xml interfaces</a></td><td>Dodgy code</td></tr>
</table>
<h2>Descriptions</h2>
<h3><a name="AM_CREATES_EMPTY_JAR_FILE_ENTRY">AM: Creates an empty jar file entry (AM_CREATES_EMPTY_JAR_FILE_ENTRY)</a></h3>
<p>The code calls <code>putNextEntry()</code>, immediately
followed by a call to <code>closeEntry()</code>. This results
in an empty JarFile entry. The contents of the entry
should be written to the JarFile between the calls to
<code>putNextEntry()</code> and
<code>closeEntry()</code>.</p>
<h3><a name="AM_CREATES_EMPTY_ZIP_FILE_ENTRY">AM: Creates an empty zip file entry (AM_CREATES_EMPTY_ZIP_FILE_ENTRY)</a></h3>
<p>The code calls <code>putNextEntry()</code>, immediately
followed by a call to <code>closeEntry()</code>. This results
in an empty ZipFile entry. The contents of the entry
should be written to the ZipFile between the calls to
<code>putNextEntry()</code> and
<code>closeEntry()</code>.</p>
<h3><a name="BC_EQUALS_METHOD_SHOULD_WORK_FOR_ALL_OBJECTS">BC: Equals method should not assume anything about the type of its argument (BC_EQUALS_METHOD_SHOULD_WORK_FOR_ALL_OBJECTS)</a></h3>
<p>
The <code>equals(Object o)</code> method shouldn't make any assumptions
about the type of <code>o</code>. It should simply return
false if <code>o</code> is not the same type as <code>this</code>.
</p>
<h3><a name="BIT_SIGNED_CHECK">BIT: Check for sign of bitwise operation (BIT_SIGNED_CHECK)</a></h3>
<p> This method compares an expression such as
<pre>((event.detail &amp; SWT.SELECTED) &gt; 0)</pre>.
Using bit arithmetic and then comparing with the greater than operator can
lead to unexpected results (of course depending on the value of
SWT.SELECTED). If SWT.SELECTED is a negative number, this is a candidate
for a bug. Even when SWT.SELECTED is not negative, it seems good practice
to use '!= 0' instead of '&gt; 0'.
</p>
<p>
<em>Boris Bokowski</em>
</p>
<h3><a name="CN_IDIOM">CN: Class implements Cloneable but does not define or use clone method (CN_IDIOM)</a></h3>
<p>
Class implements Cloneable but does not define or
use the clone method.</p>
<h3><a name="CN_IDIOM_NO_SUPER_CALL">CN: clone method does not call super.clone() (CN_IDIOM_NO_SUPER_CALL)</a></h3>
<p> This non-final class defines a clone() method that does not call super.clone().
If this class ("<i>A</i>") is extended by a subclass ("<i>B</i>"),
and the subclass <i>B</i> calls super.clone(), then it is likely that
<i>B</i>'s clone() method will return an object of type <i>A</i>,
which violates the standard contract for clone().</p>
<p> If all clone() methods call super.clone(), then they are guaranteed
to use Object.clone(), which always returns an object of the correct type.</p>
<h3><a name="CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE">CN: Class defines clone() but doesn't implement Cloneable (CN_IMPLEMENTS_CLONE_BUT_NOT_CLONEABLE)</a></h3>
<p> This class defines a clone() method but the class doesn't implement Cloneable.
There are some situations in which this is OK (e.g., you want to control how subclasses
can clone themselves), but just make sure that this is what you intended.
</p>
<h3><a name="CO_ABSTRACT_SELF">Co: Abstract class defines covariant compareTo() method (CO_ABSTRACT_SELF)</a></h3>
<p> This class defines a covariant version of <code>compareTo()</code>.&nbsp;
To correctly override the <code>compareTo()</code> method in the
<code>Comparable</code> interface, the parameter of <code>compareTo()</code>
must have type <code>java.lang.Object</code>.</p>
<h3><a name="CO_SELF_NO_OBJECT">Co: Covariant compareTo() method defined (CO_SELF_NO_OBJECT)</a></h3>
<p> This class defines a covariant version of <code>compareTo()</code>.&nbsp;
To correctly override the <code>compareTo()</code> method in the
<code>Comparable</code> interface, the parameter of <code>compareTo()</code>
must have type <code>java.lang.Object</code>.</p>
<h3><a name="DE_MIGHT_DROP">DE: Method might drop exception (DE_MIGHT_DROP)</a></h3>
<p> This method might drop an exception.&nbsp; In general, exceptions
should be handled or reported in some way, or they should be thrown
out of the method.</p>
<h3><a name="DE_MIGHT_IGNORE">DE: Method might ignore exception (DE_MIGHT_IGNORE)</a></h3>
<p> This method might ignore an exception.&nbsp; In general, exceptions
should be handled or reported in some way, or they should be thrown
out of the method.</p>
<h3><a name="DMI_ENTRY_SETS_MAY_REUSE_ENTRY_OBJECTS">DMI: Adding elements of an entry set may fail due to reuse of Entry objects (DMI_ENTRY_SETS_MAY_REUSE_ENTRY_OBJECTS)</a></h3>
<p> The entrySet() method is allowed to return a view of the
underlying Map in which a single Entry object is reused and returned
during the iteration. As of Java 1.6, both IdentityHashMap
and EnumMap did so. When iterating through such a Map,
the Entry value is only valid until you advance to the next iteration.
If, for example, you try to pass such an entrySet to an addAll method,
things will go badly wrong.
</p>
<h3><a name="DMI_RANDOM_USED_ONLY_ONCE">DMI: Random object created and used only once (DMI_RANDOM_USED_ONLY_ONCE)</a></h3>
<p> This code creates a java.util.Random object, uses it to generate one random number, and then discards
the Random object. This produces mediocre quality random numbers and is inefficient.
If possible, rewrite the code so that the Random object is created once and saved, and each time a new random number
is required invoke a method on the existing Random object to obtain it.
</p>
<p>If it is important that the generated Random numbers not be guessable, you <em>must</em> not create a new Random for each random
number; the values are too easily guessable. You should strongly consider using a java.security.SecureRandom instead
(and avoid allocating a new SecureRandom for each random number needed).
</p>
<h3><a name="DMI_USING_REMOVEALL_TO_CLEAR_COLLECTION">DMI: Don't use removeAll to clear a collection (DMI_USING_REMOVEALL_TO_CLEAR_COLLECTION)</a></h3>
<p> If you want to remove all elements from a collection <code>c</code>, use <code>c.clear</code>,
not <code>c.removeAll(c)</code>. Calling <code>c.removeAll(c)</code> to clear a collection
is less clear, susceptible to errors from typos, less efficient and
for some collections, might throw a <code>ConcurrentModificationException</code>.
</p>
<h3><a name="DM_EXIT">Dm: Method invokes System.exit(...) (DM_EXIT)</a></h3>
<p> Invoking System.exit shuts down the entire Java virtual machine. This
should only been done when it is appropriate. Such calls make it
hard or impossible for your code to be invoked by other code.
Consider throwing a RuntimeException instead.</p>
<h3><a name="DM_RUN_FINALIZERS_ON_EXIT">Dm: Method invokes dangerous method runFinalizersOnExit (DM_RUN_FINALIZERS_ON_EXIT)</a></h3>
<p> <em>Never call System.runFinalizersOnExit
or Runtime.runFinalizersOnExit for any reason: they are among the most
dangerous methods in the Java libraries.</em> -- Joshua Bloch</p>
<h3><a name="ES_COMPARING_PARAMETER_STRING_WITH_EQ">ES: Comparison of String parameter using == or != (ES_COMPARING_PARAMETER_STRING_WITH_EQ)</a></h3>
<p>This code compares a <code>java.lang.String</code> parameter for reference
equality using the == or != operators. Requiring callers to
pass only String constants or interned strings to a method is unnecessarily
fragile, and rarely leads to measurable performance gains. Consider
using the <code>equals(Object)</code> method instead.</p>
<h3><a name="ES_COMPARING_STRINGS_WITH_EQ">ES: Comparison of String objects using == or != (ES_COMPARING_STRINGS_WITH_EQ)</a></h3>
<p>This code compares <code>java.lang.String</code> objects for reference
equality using the == or != operators.
Unless both strings are either constants in a source file, or have been
interned using the <code>String.intern()</code> method, the same string
value may be represented by two different String objects. Consider
using the <code>equals(Object)</code> method instead.</p>
<h3><a name="EQ_ABSTRACT_SELF">Eq: Abstract class defines covariant equals() method (EQ_ABSTRACT_SELF)</a></h3>
<p> This class defines a covariant version of <code>equals()</code>.&nbsp;
To correctly override the <code>equals()</code> method in
<code>java.lang.Object</code>, the parameter of <code>equals()</code>
must have type <code>java.lang.Object</code>.</p>
<h3><a name="EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS">Eq: Equals checks for incompatible operand (EQ_CHECK_FOR_OPERAND_NOT_COMPATIBLE_WITH_THIS)</a></h3>
<p> This equals method is checking to see if the argument is some incompatible type
(i.e., a class that is neither a supertype nor subtype of the class that defines
the equals method). For example, the Foo class might have an equals method
that looks like:
<p><code><pre>
public boolean equals(Object o) {
if (o instanceof Foo)
return name.equals(((Foo)o).name);
else if (o instanceof String)
return name.equals(o);
else return false;
</pre></code></p>
<p>This is considered bad practice, as it makes it very hard to implement an equals method that
is symmetric and transitive. Without those properties, very unexpected behavoirs are possible.
</p>
<h3><a name="EQ_COMPARETO_USE_OBJECT_EQUALS">Eq: Class defines compareTo(...) and uses Object.equals() (EQ_COMPARETO_USE_OBJECT_EQUALS)</a></h3>
<p> This class defines a <code>compareTo(...)</code> method but inherits its
<code>equals()</code> method from <code>java.lang.Object</code>.
Generally, the value of compareTo should return zero if and only if
equals returns true. If this is violated, weird and unpredictable
failures will occur in classes such as PriorityQueue.
In Java 5 the PriorityQueue.remove method uses the compareTo method,
while in Java 6 it uses the equals method.
<p>From the JavaDoc for the compareTo method in the Comparable interface:
<blockquote>
It is strongly recommended, but not strictly required that <code>(x.compareTo(y)==0) == (x.equals(y))</code>.
Generally speaking, any class that implements the Comparable interface and violates this condition
should clearly indicate this fact. The recommended language
is "Note: this class has a natural ordering that is inconsistent with equals."
</blockquote>
<h3><a name="EQ_GETCLASS_AND_CLASS_CONSTANT">Eq: equals method fails for subtypes (EQ_GETCLASS_AND_CLASS_CONSTANT)</a></h3>
<p> This class has an equals method that will be broken if it is inherited by subclasses.
It compares a class literal with the class of the argument (e.g., in class <code>Foo</code>
it might check if <code>Foo.class == o.getClass()</code>).
It is better to check if <code>this.getClass() == o.getClass()</code>.
</p>
<h3><a name="EQ_SELF_NO_OBJECT">Eq: Covariant equals() method defined (EQ_SELF_NO_OBJECT)</a></h3>
<p> This class defines a covariant version of <code>equals()</code>.&nbsp;
To correctly override the <code>equals()</code> method in
<code>java.lang.Object</code>, the parameter of <code>equals()</code>
must have type <code>java.lang.Object</code>.</p>
<h3><a name="FI_EMPTY">FI: Empty finalizer should be deleted (FI_EMPTY)</a></h3>
<p> Empty <code>finalize()</code> methods are useless, so they should
be deleted.</p>
<h3><a name="FI_EXPLICIT_INVOCATION">FI: Explicit invocation of finalizer (FI_EXPLICIT_INVOCATION)</a></h3>
<p> This method contains an explicit invocation of the <code>finalize()</code>
method on an object.&nbsp; Because finalizer methods are supposed to be
executed once, and only by the VM, this is a bad idea.</p>
<p>If a connected set of objects beings finalizable, then the VM will invoke the
finalize method on all the finalizable object, possibly at the same time in different threads.
Thus, it is a particularly bad idea, in the finalize method for a class X, invoke finalize
on objects referenced by X, because they may already be getting finalized in a separate thread.
<h3><a name="FI_FINALIZER_NULLS_FIELDS">FI: Finalizer nulls fields (FI_FINALIZER_NULLS_FIELDS)</a></h3>
<p> This finalizer nulls out fields. This is usually an error, as it does not aid garbage collection,
and the object is going to be garbage collected anyway.
<h3><a name="FI_FINALIZER_ONLY_NULLS_FIELDS">FI: Finalizer only nulls fields (FI_FINALIZER_ONLY_NULLS_FIELDS)</a></h3>
<p> This finalizer does nothing except null out fields. This is completely pointless, and requires that
the object be garbage collected, finalized, and then garbage collected again. You should just remove the finalize
method.
<h3><a name="FI_MISSING_SUPER_CALL">FI: Finalizer does not call superclass finalizer (FI_MISSING_SUPER_CALL)</a></h3>
<p> This <code>finalize()</code> method does not make a call to its
superclass's <code>finalize()</code> method.&nbsp; So, any finalizer
actions defined for the superclass will not be performed.&nbsp;
Add a call to <code>super.finalize()</code>.</p>
<h3><a name="FI_NULLIFY_SUPER">FI: Finalizer nullifies superclass finalizer (FI_NULLIFY_SUPER)</a></h3>
<p> This empty <code>finalize()</code> method explicitly negates the
effect of any finalizer defined by its superclass.&nbsp; Any finalizer
actions defined for the superclass will not be performed.&nbsp;
Unless this is intended, delete this method.</p>
<h3><a name="FI_USELESS">FI: Finalizer does nothing but call superclass finalizer (FI_USELESS)</a></h3>
<p> The only thing this <code>finalize()</code> method does is call
the superclass's <code>finalize()</code> method, making it
redundant.&nbsp; Delete it.</p>
<h3><a name="VA_FORMAT_STRING_USES_NEWLINE">FS: Format string should use %n rather than \n (VA_FORMAT_STRING_USES_NEWLINE)</a></h3>
<p>
This format string include a newline character (\n). In format strings, it is generally
preferable better to use %n, which will produce the platform-specific line separator.
</p>
<h3><a name="GC_UNCHECKED_TYPE_IN_GENERIC_CALL">GC: Unchecked type in generic call (GC_UNCHECKED_TYPE_IN_GENERIC_CALL)</a></h3>
<p> This call to a generic collection method passes an argument
while compile type Object where a specific type from
the generic type parameters is expected.
Thus, neither the standard Java type system nor static analysis
can provide useful information on whether the
object being passed as a parameter is of an appropriate type.
</p>
<h3><a name="HE_EQUALS_NO_HASHCODE">HE: Class defines equals() but not hashCode() (HE_EQUALS_NO_HASHCODE)</a></h3>
<p> This class overrides <code>equals(Object)</code>, but does not
override <code>hashCode()</code>.&nbsp; Therefore, the class may violate the
invariant that equal objects must have equal hashcodes.</p>
<h3><a name="HE_EQUALS_USE_HASHCODE">HE: Class defines equals() and uses Object.hashCode() (HE_EQUALS_USE_HASHCODE)</a></h3>
<p> This class overrides <code>equals(Object)</code>, but does not
override <code>hashCode()</code>, and inherits the implementation of
<code>hashCode()</code> from <code>java.lang.Object</code> (which returns
the identity hash code, an arbitrary value assigned to the object
by the VM).&nbsp; Therefore, the class is very likely to violate the
invariant that equal objects must have equal hashcodes.</p>
<p>If you don't think instances of this class will ever be inserted into a HashMap/HashTable,
the recommended <code>hashCode</code> implementation to use is:</p>
<pre>public int hashCode() {
assert false : "hashCode not designed";
return 42; // any arbitrary constant will do
}</pre>
<h3><a name="HE_HASHCODE_NO_EQUALS">HE: Class defines hashCode() but not equals() (HE_HASHCODE_NO_EQUALS)</a></h3>
<p> This class defines a <code>hashCode()</code> method but not an
<code>equals()</code> method.&nbsp; Therefore, the class may
violate the invariant that equal objects must have equal hashcodes.</p>
<h3><a name="HE_HASHCODE_USE_OBJECT_EQUALS">HE: Class defines hashCode() and uses Object.equals() (HE_HASHCODE_USE_OBJECT_EQUALS)</a></h3>
<p> This class defines a <code>hashCode()</code> method but inherits its
<code>equals()</code> method from <code>java.lang.Object</code>
(which defines equality by comparing object references).&nbsp; Although
this will probably satisfy the contract that equal objects must have
equal hashcodes, it is probably not what was intended by overriding
the <code>hashCode()</code> method.&nbsp; (Overriding <code>hashCode()</code>
implies that the object's identity is based on criteria more complicated
than simple reference equality.)</p>
<p>If you don't think instances of this class will ever be inserted into a HashMap/HashTable,
the recommended <code>hashCode</code> implementation to use is:</p>
<p><pre>public int hashCode() {
assert false : "hashCode not designed";
return 42; // any arbitrary constant will do
}</pre></p>
<h3><a name="HE_INHERITS_EQUALS_USE_HASHCODE">HE: Class inherits equals() and uses Object.hashCode() (HE_INHERITS_EQUALS_USE_HASHCODE)</a></h3>
<p> This class inherits <code>equals(Object)</code> from an abstract
superclass, and <code>hashCode()</code> from
<code>java.lang.Object</code> (which returns
the identity hash code, an arbitrary value assigned to the object
by the VM).&nbsp; Therefore, the class is very likely to violate the
invariant that equal objects must have equal hashcodes.</p>
<p>If you don't want to define a hashCode method, and/or don't
believe the object will ever be put into a HashMap/Hashtable,
define the <code>hashCode()</code> method
to throw <code>UnsupportedOperationException</code>.</p>
<h3><a name="IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION">IC: Superclass uses subclass during initialization (IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION)</a></h3>
<p> During the initialization of a class, the class makes an active use of a subclass.
That subclass will not yet be initialized at the time of this use.
For example, in the following code, <code>foo</code> will be null.</p>
<pre>
public class CircularClassInitialization {
static class InnerClassSingleton extends CircularClassInitialization {
static InnerClassSingleton singleton = new InnerClassSingleton();
}
static CircularClassInitialization foo = InnerClassSingleton.singleton;
}
</pre>
<h3><a name="IMSE_DONT_CATCH_IMSE">IMSE: Dubious catching of IllegalMonitorStateException (IMSE_DONT_CATCH_IMSE)</a></h3>
<p>IllegalMonitorStateException is generally only
thrown in case of a design flaw in your code (calling wait or
notify on an object you do not hold a lock on).</p>
<h3><a name="ISC_INSTANTIATE_STATIC_CLASS">ISC: Needless instantiation of class that only supplies static methods (ISC_INSTANTIATE_STATIC_CLASS)</a></h3>
<p> This class allocates an object that is based on a class that only supplies static methods. This object
does not need to be created, just access the static methods directly using the class name as a qualifier.</p>
<h3><a name="IT_NO_SUCH_ELEMENT">It: Iterator next() method can't throw NoSuchElementException (IT_NO_SUCH_ELEMENT)</a></h3>
<p> This class implements the <code>java.util.Iterator</code> interface.&nbsp;
However, its <code>next()</code> method is not capable of throwing
<code>java.util.NoSuchElementException</code>.&nbsp; The <code>next()</code>
method should be changed so it throws <code>NoSuchElementException</code>
if is called when there are no more elements to return.</p>
<h3><a name="J2EE_STORE_OF_NON_SERIALIZABLE_OBJECT_INTO_SESSION">J2EE: Store of non serializable object into HttpSession (J2EE_STORE_OF_NON_SERIALIZABLE_OBJECT_INTO_SESSION)</a></h3>
<p>
This code seems to be storing a non-serializable object into an HttpSession.
If this session is passivated or migrated, an error will result.
</p>
<h3><a name="JCIP_FIELD_ISNT_FINAL_IN_IMMUTABLE_CLASS">JCIP: Fields of immutable classes should be final (JCIP_FIELD_ISNT_FINAL_IN_IMMUTABLE_CLASS)</a></h3>
<p> The class is annotated with net.jcip.annotations.Immutable, and the rules for that annotation require
that all fields are final.
.</p>
<h3><a name="NP_BOOLEAN_RETURN_NULL">NP: Method with Boolean return type returns explicit null (NP_BOOLEAN_RETURN_NULL)</a></h3>
<p>
A method that returns either Boolean.TRUE, Boolean.FALSE or null is an accident waiting to happen.
This method can be invoked as though it returned a value of type boolean, and
the compiler will insert automatic unboxing of the Boolean value. If a null value is returned,
this will result in a NullPointerException.
</p>
<h3><a name="NP_CLONE_COULD_RETURN_NULL">NP: Clone method may return null (NP_CLONE_COULD_RETURN_NULL)</a></h3>
<p>
This clone method seems to return null in some circumstances, but clone is never
allowed to return a null value. If you are convinced this path is unreachable, throw an AssertionError
instead.
</p>
<h3><a name="NP_EQUALS_SHOULD_HANDLE_NULL_ARGUMENT">NP: equals() method does not check for null argument (NP_EQUALS_SHOULD_HANDLE_NULL_ARGUMENT)</a></h3>
<p>
This implementation of equals(Object) violates the contract defined
by java.lang.Object.equals() because it does not check for null
being passed as the argument. All equals() methods should return
false if passed a null value.
</p>
<h3><a name="NP_TOSTRING_COULD_RETURN_NULL">NP: toString method may return null (NP_TOSTRING_COULD_RETURN_NULL)</a></h3>
<p>
This toString method seems to return null in some circumstances. A liberal reading of the
spec could be interpreted as allowing this, but it is probably a bad idea and could cause
other code to break. Return the empty string or some other appropriate string rather than null.
</p>
<h3><a name="NM_CLASS_NAMING_CONVENTION">Nm: Class names should start with an upper case letter (NM_CLASS_NAMING_CONVENTION)</a></h3>
<p> Class names should be nouns, in mixed case with the first letter of each internal word capitalized. Try to keep your class names simple and descriptive. Use whole words-avoid acronyms and abbreviations (unless the abbreviation is much more widely used than the long form, such as URL or HTML).
</p>
<h3><a name="NM_CLASS_NOT_EXCEPTION">Nm: Class is not derived from an Exception, even though it is named as such (NM_CLASS_NOT_EXCEPTION)</a></h3>
<p> This class is not derived from another exception, but ends with 'Exception'. This will
be confusing to users of this class.</p>
<h3><a name="NM_CONFUSING">Nm: Confusing method names (NM_CONFUSING)</a></h3>
<p> The referenced methods have names that differ only by capitalization.</p>
<h3><a name="NM_FIELD_NAMING_CONVENTION">Nm: Field names should start with a lower case letter (NM_FIELD_NAMING_CONVENTION)</a></h3>
<p>
Names of fields that are not final should be in mixed case with a lowercase first letter and the first letters of subsequent words capitalized.
</p>
<h3><a name="NM_FUTURE_KEYWORD_USED_AS_IDENTIFIER">Nm: Use of identifier that is a keyword in later versions of Java (NM_FUTURE_KEYWORD_USED_AS_IDENTIFIER)</a></h3>
<p>The identifier is a word that is reserved as a keyword in later versions of Java, and your code will need to be changed
in order to compile it in later versions of Java.</p>
<h3><a name="NM_FUTURE_KEYWORD_USED_AS_MEMBER_IDENTIFIER">Nm: Use of identifier that is a keyword in later versions of Java (NM_FUTURE_KEYWORD_USED_AS_MEMBER_IDENTIFIER)</a></h3>
<p>This identifier is used as a keyword in later versions of Java. This code, and
any code that references this API,
will need to be changed in order to compile it in later versions of Java.</p>
<h3><a name="NM_METHOD_NAMING_CONVENTION">Nm: Method names should start with a lower case letter (NM_METHOD_NAMING_CONVENTION)</a></h3>
<p>
Methods should be verbs, in mixed case with the first letter lowercase, with the first letter of each internal word capitalized.
</p>
<h3><a name="NM_SAME_SIMPLE_NAME_AS_INTERFACE">Nm: Class names shouldn't shadow simple name of implemented interface (NM_SAME_SIMPLE_NAME_AS_INTERFACE)</a></h3>
<p> This class/interface has a simple name that is identical to that of an implemented/extended interface, except
that the interface is in a different package (e.g., <code>alpha.Foo</code> extends <code>beta.Foo</code>).
This can be exceptionally confusing, create lots of situations in which you have to look at import statements
to resolve references and creates many
opportunities to accidently define methods that do not override methods in their superclasses.
</p>
<h3><a name="NM_SAME_SIMPLE_NAME_AS_SUPERCLASS">Nm: Class names shouldn't shadow simple name of superclass (NM_SAME_SIMPLE_NAME_AS_SUPERCLASS)</a></h3>
<p> This class has a simple name that is identical to that of its superclass, except
that its superclass is in a different package (e.g., <code>alpha.Foo</code> extends <code>beta.Foo</code>).
This can be exceptionally confusing, create lots of situations in which you have to look at import statements
to resolve references and creates many
opportunities to accidently define methods that do not override methods in their superclasses.
</p>
<h3><a name="NM_VERY_CONFUSING_INTENTIONAL">Nm: Very confusing method names (but perhaps intentional) (NM_VERY_CONFUSING_INTENTIONAL)</a></h3>
<p> The referenced methods have names that differ only by capitalization.
This is very confusing because if the capitalization were
identical then one of the methods would override the other. From the existence of other methods, it
seems that the existence of both of these methods is intentional, but is sure is confusing.
You should try hard to eliminate one of them, unless you are forced to have both due to frozen APIs.
</p>
<h3><a name="NM_WRONG_PACKAGE_INTENTIONAL">Nm: Method doesn't override method in superclass due to wrong package for parameter (NM_WRONG_PACKAGE_INTENTIONAL)</a></h3>
<p> The method in the subclass doesn't override a similar method in a superclass because the type of a parameter doesn't exactly match
the type of the corresponding parameter in the superclass. For example, if you have:</p>
<blockquote>
<pre>
import alpha.Foo;
public class A {
public int f(Foo x) { return 17; }
}
----
import beta.Foo;
public class B extends A {
public int f(Foo x) { return 42; }
public int f(alpha.Foo x) { return 27; }
}
</pre>
</blockquote>
<p>The <code>f(Foo)</code> method defined in class <code>B</code> doesn't
override the
<code>f(Foo)</code> method defined in class <code>A</code>, because the argument
types are <code>Foo</code>'s from different packages.
</p>
<p>In this case, the subclass does define a method with a signature identical to the method in the superclass,
so this is presumably understood. However, such methods are exceptionally confusing. You should strongly consider
removing or deprecating the method with the similar but not identical signature.
</p>
<h3><a name="ODR_OPEN_DATABASE_RESOURCE">ODR: Method may fail to close database resource (ODR_OPEN_DATABASE_RESOURCE)</a></h3>
<p> The method creates a database resource (such as a database connection
or row set), does not assign it to any
fields, pass it to other methods, or return it, and does not appear to close
the object on all paths out of the method.&nbsp; Failure to
close database resources on all paths out of a method may
result in poor performance, and could cause the application to
have problems communicating with the database.
</p>
<h3><a name="ODR_OPEN_DATABASE_RESOURCE_EXCEPTION_PATH">ODR: Method may fail to close database resource on exception (ODR_OPEN_DATABASE_RESOURCE_EXCEPTION_PATH)</a></h3>
<p> The method creates a database resource (such as a database connection
or row set), does not assign it to any
fields, pass it to other methods, or return it, and does not appear to close
the object on all exception paths out of the method.&nbsp; Failure to
close database resources on all paths out of a method may
result in poor performance, and could cause the application to
have problems communicating with the database.</p>
<h3><a name="OS_OPEN_STREAM">OS: Method may fail to close stream (OS_OPEN_STREAM)</a></h3>
<p> The method creates an IO stream object, does not assign it to any
fields, pass it to other methods that might close it,
or return it, and does not appear to close
the stream on all paths out of the method.&nbsp; This may result in
a file descriptor leak.&nbsp; It is generally a good
idea to use a <code>finally</code> block to ensure that streams are
closed.</p>
<h3><a name="OS_OPEN_STREAM_EXCEPTION_PATH">OS: Method may fail to close stream on exception (OS_OPEN_STREAM_EXCEPTION_PATH)</a></h3>
<p> The method creates an IO stream object, does not assign it to any
fields, pass it to other methods, or return it, and does not appear to close
it on all possible exception paths out of the method.&nbsp;
This may result in a file descriptor leak.&nbsp; It is generally a good
idea to use a <code>finally</code> block to ensure that streams are
closed.</p>
<h3><a name="PZ_DONT_REUSE_ENTRY_OBJECTS_IN_ITERATORS">PZ: Don't reuse entry objects in iterators (PZ_DONT_REUSE_ENTRY_OBJECTS_IN_ITERATORS)</a></h3>
<p> The entrySet() method is allowed to return a view of the
underlying Map in which an Iterator and Map.Entry. This clever
idea was used in several Map implementations, but introduces the possibility
of nasty coding mistakes. If a map <code>m</code> returns
such an iterator for an entrySet, then
<code>c.addAll(m.entrySet())</code> will go badly wrong. All of
the Map implementations in OpenJDK 1.7 have been rewritten to avoid this,
you should to.
</p>
<h3><a name="RC_REF_COMPARISON_BAD_PRACTICE">RC: Suspicious reference comparison to constant (RC_REF_COMPARISON_BAD_PRACTICE)</a></h3>
<p> This method compares a reference value to a constant using the == or != operator,
where the correct way to compare instances of this type is generally
with the equals() method.
It is possible to create distinct instances that are equal but do not compare as == since
they are different objects.
Examples of classes which should generally
not be compared by reference are java.lang.Integer, java.lang.Float, etc.</p>
<h3><a name="RC_REF_COMPARISON_BAD_PRACTICE_BOOLEAN">RC: Suspicious reference comparison of Boolean values (RC_REF_COMPARISON_BAD_PRACTICE_BOOLEAN)</a></h3>
<p> This method compares two Boolean values using the == or != operator.
Normally, there are only two Boolean values (Boolean.TRUE and Boolean.FALSE),
but it is possible to create other Boolean objects using the <code>new Boolean(b)</code>
constructor. It is best to avoid such objects, but if they do exist,
then checking Boolean objects for equality using == or != will give results
than are different than you would get using <code>.equals(...)</code>
</p>
<h3><a name="RR_NOT_CHECKED">RR: Method ignores results of InputStream.read() (RR_NOT_CHECKED)</a></h3>
<p> This method ignores the return value of one of the variants of
<code>java.io.InputStream.read()</code> which can return multiple bytes.&nbsp;
If the return value is not checked, the caller will not be able to correctly
handle the case where fewer bytes were read than the caller requested.&nbsp;
This is a particularly insidious kind of bug, because in many programs,
reads from input streams usually do read the full amount of data requested,
causing the program to fail only sporadically.</p>
<h3><a name="SR_NOT_CHECKED">RR: Method ignores results of InputStream.skip() (SR_NOT_CHECKED)</a></h3>
<p> This method ignores the return value of
<code>java.io.InputStream.skip()</code> which can skip multiple bytes.&nbsp;
If the return value is not checked, the caller will not be able to correctly
handle the case where fewer bytes were skipped than the caller requested.&nbsp;
This is a particularly insidious kind of bug, because in many programs,
skips from input streams usually do skip the full amount of data requested,
causing the program to fail only sporadically. With Buffered streams, however,
skip() will only skip data in the buffer, and will routinely fail to skip the
requested number of bytes.</p>
<h3><a name="RV_NEGATING_RESULT_OF_COMPARETO">RV: Negating the result of compareTo()/compare() (RV_NEGATING_RESULT_OF_COMPARETO)</a></h3>
<p> This code negatives the return value of a compareTo or compare method.
This is a questionable or bad programming practice, since if the return
value is Integer.MIN_VALUE, negating the return value won't
negate the sign of the result. You can achieve the same intended result
by reversing the order of the operands rather than by negating the results.
</p>
<h3><a name="RV_RETURN_VALUE_IGNORED_BAD_PRACTICE">RV: Method ignores exceptional return value (RV_RETURN_VALUE_IGNORED_BAD_PRACTICE)</a></h3>
<p> This method returns a value that is not checked. The return value should be checked
since it can indicate an unusual or unexpected function execution. For
example, the <code>File.delete()</code> method returns false
if the file could not be successfully deleted (rather than
throwing an Exception).
If you don't check the result, you won't notice if the method invocation
signals unexpected behavior by returning an atypical return value.
</p>
<h3><a name="SI_INSTANCE_BEFORE_FINALS_ASSIGNED">SI: Static initializer creates instance before all static final fields assigned (SI_INSTANCE_BEFORE_FINALS_ASSIGNED)</a></h3>
<p> The class's static initializer creates an instance of the class
before all of the static final fields are assigned.</p>
<h3><a name="SW_SWING_METHODS_INVOKED_IN_SWING_THREAD">SW: Certain swing methods needs to be invoked in Swing thread (SW_SWING_METHODS_INVOKED_IN_SWING_THREAD)</a></h3>
<p>(<a href="http://web.archive.org/web/20090526170426/http://java.sun.com/developer/JDCTechTips/2003/tt1208.html">From JDC Tech Tip</a>): The Swing methods
show(), setVisible(), and pack() will create the associated peer for the frame.
With the creation of the peer, the system creates the event dispatch thread.
This makes things problematic because the event dispatch thread could be notifying
listeners while pack and validate are still processing. This situation could result in
two threads going through the Swing component-based GUI -- it's a serious flaw that
could result in deadlocks or other related threading issues. A pack call causes
components to be realized. As they are being realized (that is, not necessarily
visible), they could trigger listener notification on the event dispatch thread.</p>
<h3><a name="SE_BAD_FIELD">Se: Non-transient non-serializable instance field in serializable class (SE_BAD_FIELD)</a></h3>
<p> This Serializable class defines a non-primitive instance field which is neither transient,
Serializable, or <code>java.lang.Object</code>, and does not appear to implement
the <code>Externalizable</code> interface or the
<code>readObject()</code> and <code>writeObject()</code> methods.&nbsp;
Objects of this class will not be deserialized correctly if a non-Serializable
object is stored in this field.</p>
<h3><a name="SE_BAD_FIELD_INNER_CLASS">Se: Non-serializable class has a serializable inner class (SE_BAD_FIELD_INNER_CLASS)</a></h3>
<p> This Serializable class is an inner class of a non-serializable class.
Thus, attempts to serialize it will also attempt to associate instance of the outer
class with which it is associated, leading to a runtime error.
</p>
<p>If possible, making the inner class a static inner class should solve the
problem. Making the outer class serializable might also work, but that would
mean serializing an instance of the inner class would always also serialize the instance
of the outer class, which it often not what you really want.
<h3><a name="SE_BAD_FIELD_STORE">Se: Non-serializable value stored into instance field of a serializable class (SE_BAD_FIELD_STORE)</a></h3>
<p> A non-serializable value is stored into a non-transient field
of a serializable class.</p>
<h3><a name="SE_COMPARATOR_SHOULD_BE_SERIALIZABLE">Se: Comparator doesn't implement Serializable (SE_COMPARATOR_SHOULD_BE_SERIALIZABLE)</a></h3>
<p> This class implements the <code>Comparator</code> interface. You
should consider whether or not it should also implement the <code>Serializable</code>
interface. If a comparator is used to construct an ordered collection
such as a <code>TreeMap</code>, then the <code>TreeMap</code>
will be serializable only if the comparator is also serializable.
As most comparators have little or no state, making them serializable
is generally easy and good defensive programming.
</p>
<h3><a name="SE_INNER_CLASS">Se: Serializable inner class (SE_INNER_CLASS)</a></h3>
<p> This Serializable class is an inner class. Any attempt to serialize
it will also serialize the associated outer instance. The outer instance is serializable,
so this won't fail, but it might serialize a lot more data than intended.
If possible, making the inner class a static inner class (also known as a nested class) should solve the
problem.
<h3><a name="SE_NONFINAL_SERIALVERSIONID">Se: serialVersionUID isn't final (SE_NONFINAL_SERIALVERSIONID)</a></h3>
<p> This class defines a <code>serialVersionUID</code> field that is not final.&nbsp;
The field should be made final
if it is intended to specify
the version UID for purposes of serialization.</p>
<h3><a name="SE_NONLONG_SERIALVERSIONID">Se: serialVersionUID isn't long (SE_NONLONG_SERIALVERSIONID)</a></h3>
<p> This class defines a <code>serialVersionUID</code> field that is not long.&nbsp;
The field should be made long
if it is intended to specify
the version UID for purposes of serialization.</p>
<h3><a name="SE_NONSTATIC_SERIALVERSIONID">Se: serialVersionUID isn't static (SE_NONSTATIC_SERIALVERSIONID)</a></h3>
<p> This class defines a <code>serialVersionUID</code> field that is not static.&nbsp;
The field should be made static
if it is intended to specify
the version UID for purposes of serialization.</p>
<h3><a name="SE_NO_SUITABLE_CONSTRUCTOR">Se: Class is Serializable but its superclass doesn't define a void constructor (SE_NO_SUITABLE_CONSTRUCTOR)</a></h3>
<p> This class implements the <code>Serializable</code> interface
and its superclass does not. When such an object is deserialized,
the fields of the superclass need to be initialized by
invoking the void constructor of the superclass.
Since the superclass does not have one,
serialization and deserialization will fail at runtime.</p>
<h3><a name="SE_NO_SUITABLE_CONSTRUCTOR_FOR_EXTERNALIZATION">Se: Class is Externalizable but doesn't define a void constructor (SE_NO_SUITABLE_CONSTRUCTOR_FOR_EXTERNALIZATION)</a></h3>
<p> This class implements the <code>Externalizable</code> interface, but does
not define a void constructor. When Externalizable objects are deserialized,
they first need to be constructed by invoking the void
constructor. Since this class does not have one,
serialization and deserialization will fail at runtime.</p>
<h3><a name="SE_READ_RESOLVE_MUST_RETURN_OBJECT">Se: The readResolve method must be declared with a return type of Object. (SE_READ_RESOLVE_MUST_RETURN_OBJECT)</a></h3>
<p> In order for the readResolve method to be recognized by the serialization
mechanism, it must be declared to have a return type of Object.
</p>
<h3><a name="SE_TRANSIENT_FIELD_NOT_RESTORED">Se: Transient field that isn't set by deserialization. (SE_TRANSIENT_FIELD_NOT_RESTORED)</a></h3>
<p> This class contains a field that is updated at multiple places in the class, thus it seems to be part of the state of the class. However, since the field is marked as transient and not set in readObject or readResolve, it will contain the default value in any
deserialized instance of the class.
</p>
<h3><a name="SE_NO_SERIALVERSIONID">SnVI: Class is Serializable, but doesn't define serialVersionUID (SE_NO_SERIALVERSIONID)</a></h3>
<p> This class implements the <code>Serializable</code> interface, but does
not define a <code>serialVersionUID</code> field.&nbsp;
A change as simple as adding a reference to a .class object
will add synthetic fields to the class,
which will unfortunately change the implicit
serialVersionUID (e.g., adding a reference to <code>String.class</code>
will generate a static field <code>class$java$lang$String</code>).
Also, different source code to bytecode compilers may use different
naming conventions for synthetic variables generated for
references to class objects or inner classes.
To ensure interoperability of Serializable across versions,
consider adding an explicit serialVersionUID.</p>
<h3><a name="UI_INHERITANCE_UNSAFE_GETRESOURCE">UI: Usage of GetResource may be unsafe if class is extended (UI_INHERITANCE_UNSAFE_GETRESOURCE)</a></h3>
<p>Calling <code>this.getClass().getResource(...)</code> could give
results other than expected if this class is extended by a class in
another package.</p>
<h3><a name="BC_IMPOSSIBLE_CAST">BC: Impossible cast (BC_IMPOSSIBLE_CAST)</a></h3>
<p>
This cast will always throw a ClassCastException.
FindBugs tracks type information from instanceof checks,
and also uses more precise information about the types
of values returned from methods and loaded from fields.
Thus, it may have more precise information that just
the declared type of a variable, and can use this to determine
that a cast will always throw an exception at runtime.
</p>
<h3><a name="BC_IMPOSSIBLE_DOWNCAST">BC: Impossible downcast (BC_IMPOSSIBLE_DOWNCAST)</a></h3>
<p>
This cast will always throw a ClassCastException.
The analysis believes it knows
the precise type of the value being cast, and the attempt to
downcast it to a subtype will always fail by throwing a ClassCastException.
</p>
<h3><a name="BC_IMPOSSIBLE_DOWNCAST_OF_TOARRAY">BC: Impossible downcast of toArray() result (BC_IMPOSSIBLE_DOWNCAST_OF_TOARRAY)</a></h3>
<p>
This code is casting the result of calling <code>toArray()</code> on a collection
to a type more specific than <code>Object[]</code>, as in:
<pre>
String[] getAsArray(Collection&lt;String&gt; c) {
return (String[]) c.toArray();
}
</pre>
<p>This will usually fail by throwing a ClassCastException. The <code>toArray()</code>
of almost all collections return an <code>Object[]</code>. They can't really do anything else,
since the Collection object has no reference to the declared generic type of the collection.
<p>The correct way to do get an array of a specific type from a collection is to use
<code>c.toArray(new String[]);</code>
or <code>c.toArray(new String[c.size()]);</code> (the latter is slightly more efficient).
<p>There is one common/known exception exception to this. The <code>toArray()</code>
method of lists returned by <code>Arrays.asList(...)</code> will return a covariantly
typed array. For example, <code>Arrays.asArray(new String[] { "a" }).toArray()</code>
will return a <code>String []</code>. FindBugs attempts to detect and suppress
such cases, but may miss some.
</p>
<h3><a name="BC_IMPOSSIBLE_INSTANCEOF">BC: instanceof will always return false (BC_IMPOSSIBLE_INSTANCEOF)</a></h3>
<p>
This instanceof test will always return false. Although this is safe, make sure it isn't
an indication of some misunderstanding or some other logic error.
</p>
<h3><a name="BIT_ADD_OF_SIGNED_BYTE">BIT: Bitwise add of signed byte value (BIT_ADD_OF_SIGNED_BYTE)</a></h3>
<p> Adds a byte value and a value which is known to have the 8 lower bits clear.
Values loaded from a byte array are sign extended to 32 bits
before any any bitwise operations are performed on the value.
Thus, if <code>b[0]</code> contains the value <code>0xff</code>, and
<code>x</code> is initially 0, then the code
<code>((x &lt;&lt; 8) + b[0])</code> will sign extend <code>0xff</code>
to get <code>0xffffffff</code>, and thus give the value
<code>0xffffffff</code> as the result.
</p>
<p>In particular, the following code for packing a byte array into an int is badly wrong: </p>
<pre>
int result = 0;
for(int i = 0; i &lt; 4; i++)
result = ((result &lt;&lt; 8) + b[i]);
</pre>
<p>The following idiom will work instead: </p>
<pre>
int result = 0;
for(int i = 0; i &lt; 4; i++)
result = ((result &lt;&lt; 8) + (b[i] &amp; 0xff));
</pre>
<h3><a name="BIT_AND">BIT: Incompatible bit masks (BIT_AND)</a></h3>
<p> This method compares an expression of the form (e &amp; C) to D,
which will always compare unequal
due to the specific values of constants C and D.
This may indicate a logic error or typo.</p>
<h3><a name="BIT_AND_ZZ">BIT: Check to see if ((...) & 0) == 0 (BIT_AND_ZZ)</a></h3>
<p> This method compares an expression of the form (e &amp; 0) to 0,
which will always compare equal.
This may indicate a logic error or typo.</p>
<h3><a name="BIT_IOR">BIT: Incompatible bit masks (BIT_IOR)</a></h3>
<p> This method compares an expression of the form (e | C) to D.
which will always compare unequal
due to the specific values of constants C and D.
This may indicate a logic error or typo.</p>
<p> Typically, this bug occurs because the code wants to perform
a membership test in a bit set, but uses the bitwise OR
operator ("|") instead of bitwise AND ("&amp;").</p>
<h3><a name="BIT_IOR_OF_SIGNED_BYTE">BIT: Bitwise OR of signed byte value (BIT_IOR_OF_SIGNED_BYTE)</a></h3>
<p> Loads a byte value (e.g., a value loaded from a byte array or returned by a method
with return type byte) and performs a bitwise OR with
that value. Byte values are sign extended to 32 bits
before any any bitwise operations are performed on the value.
Thus, if <code>b[0]</code> contains the value <code>0xff</code>, and
<code>x</code> is initially 0, then the code
<code>((x &lt;&lt; 8) | b[0])</code> will sign extend <code>0xff</code>
to get <code>0xffffffff</code>, and thus give the value
<code>0xffffffff</code> as the result.
</p>
<p>In particular, the following code for packing a byte array into an int is badly wrong: </p>
<pre>
int result = 0;
for(int i = 0; i &lt; 4; i++)
result = ((result &lt;&lt; 8) | b[i]);
</pre>
<p>The following idiom will work instead: </p>
<pre>
int result = 0;
for(int i = 0; i &lt; 4; i++)
result = ((result &lt;&lt; 8) | (b[i] &amp; 0xff));
</pre>
<h3><a name="BIT_SIGNED_CHECK_HIGH_BIT">BIT: Check for sign of bitwise operation (BIT_SIGNED_CHECK_HIGH_BIT)</a></h3>
<p> This method compares an expression such as
<pre>((event.detail &amp; SWT.SELECTED) &gt; 0)</pre>.
Using bit arithmetic and then comparing with the greater than operator can
lead to unexpected results (of course depending on the value of
SWT.SELECTED). If SWT.SELECTED is a negative number, this is a candidate
for a bug. Even when SWT.SELECTED is not negative, it seems good practice
to use '!= 0' instead of '&gt; 0'.
</p>
<p>
<em>Boris Bokowski</em>
</p>
<h3><a name="BOA_BADLY_OVERRIDDEN_ADAPTER">BOA: Class overrides a method implemented in super class Adapter wrongly (BOA_BADLY_OVERRIDDEN_ADAPTER)</a></h3>
<p> This method overrides a method found in a parent class, where that class is an Adapter that implements
a listener defined in the java.awt.event or javax.swing.event package. As a result, this method will not
get called when the event occurs.</p>
<h3><a name="ICAST_BAD_SHIFT_AMOUNT">BSHIFT: 32 bit int shifted by an amount not in the range 0..31 (ICAST_BAD_SHIFT_AMOUNT)</a></h3>
<p>
The code performs shift of a 32 bit int by a constant amount outside
the range 0..31.
The effect of this is to use the lower 5 bits of the integer
value to decide how much to shift by (e.g., shifting by 40 bits is the same as shifting by 8 bits,
and shifting by 32 bits is the same as shifting by zero bits). This probably isn't what was expected,
and it is at least confusing.
</p>
<h3><a name="BX_UNBOXED_AND_COERCED_FOR_TERNARY_OPERATOR">Bx: Primitive value is unboxed and coerced for ternary operator (BX_UNBOXED_AND_COERCED_FOR_TERNARY_OPERATOR)</a></h3>
<p>A wrapped primitive value is unboxed and converted to another primitive type as part of the
evaluation of a conditional ternary operator (the <code> b ? e1 : e2</code> operator). The
semantics of Java mandate that if <code>e1</code> and <code>e2</code> are wrapped
numeric values, the values are unboxed and converted/coerced to their common type (e.g,
if <code>e1</code> is of type <code>Integer</code>
and <code>e2</code> is of type <code>Float</code>, then <code>e1</code> is unboxed,
converted to a floating point value, and boxed. See JLS Section 15.25.
</p>
<h3><a name="CO_COMPARETO_RESULTS_MIN_VALUE">Co: compareTo()/compare() returns Integer.MIN_VALUE (CO_COMPARETO_RESULTS_MIN_VALUE)</a></h3>
<p> In some situation, this compareTo or compare method returns
the constant Integer.MIN_VALUE, which is an exceptionally bad practice.
The only thing that matters about the return value of compareTo is the sign of the result.
But people will sometimes negate the return value of compareTo, expecting that this will negate
the sign of the result. And it will, except in the case where the value returned is Integer.MIN_VALUE.
So just return -1 rather than Integer.MIN_VALUE.
<h3><a name="DLS_DEAD_STORE_OF_CLASS_LITERAL">DLS: Dead store of class literal (DLS_DEAD_STORE_OF_CLASS_LITERAL)</a></h3>
<p>
This instruction assigns a class literal to a variable and then never uses it.
<a href="//java.sun.com/j2se/1.5.0/compatibility.html#literal">The behavior of this differs in Java 1.4 and in Java 5.</a>
In Java 1.4 and earlier, a reference to <code>Foo.class</code> would force the static initializer
for <code>Foo</code> to be executed, if it has not been executed already.
In Java 5 and later, it does not.
</p>
<p>See Sun's <a href="//java.sun.com/j2se/1.5.0/compatibility.html#literal">article on Java SE compatibility</a>
for more details and examples, and suggestions on how to force class initialization in Java 5.
</p>
<h3><a name="DLS_OVERWRITTEN_INCREMENT">DLS: Overwritten increment (DLS_OVERWRITTEN_INCREMENT)</a></h3>
<p>
The code performs an increment operation (e.g., <code>i++</code>) and then
immediately overwrites it. For example, <code>i = i++</code> immediately
overwrites the incremented value with the original value.
</p>
<h3><a name="DMI_ARGUMENTS_WRONG_ORDER">DMI: Reversed method arguments (DMI_ARGUMENTS_WRONG_ORDER)</a></h3>
<p> The arguments to this method call seem to be in the wrong order.
For example, a call <code>Preconditions.checkNotNull("message", message)</code>
has reserved arguments: the value to be checked is the first argument.
</p>
<h3><a name="DMI_BAD_MONTH">DMI: Bad constant value for month (DMI_BAD_MONTH)</a></h3>
<p>
This code passes a constant month
value outside the expected range of 0..11 to a method.
</p>
<h3><a name="DMI_BIGDECIMAL_CONSTRUCTED_FROM_DOUBLE">DMI: BigDecimal constructed from double that isn't represented precisely (DMI_BIGDECIMAL_CONSTRUCTED_FROM_DOUBLE)</a></h3>
<p>
This code creates a BigDecimal from a double value that doesn't translate well to a
decimal number.
For example, one might assume that writing new BigDecimal(0.1) in Java creates a BigDecimal which is exactly equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually equal to 0.1000000000000000055511151231257827021181583404541015625.
You probably want to use the BigDecimal.valueOf(double d) method, which uses the String representation
of the double to create the BigDecimal (e.g., BigDecimal.valueOf(0.1) gives 0.1).
</p>
<h3><a name="DMI_CALLING_NEXT_FROM_HASNEXT">DMI: hasNext method invokes next (DMI_CALLING_NEXT_FROM_HASNEXT)</a></h3>
<p>
The hasNext() method invokes the next() method. This is almost certainly wrong,
since the hasNext() method is not supposed to change the state of the iterator,
and the next method is supposed to change the state of the iterator.
</p>
<h3><a name="DMI_COLLECTIONS_SHOULD_NOT_CONTAIN_THEMSELVES">DMI: Collections should not contain themselves (DMI_COLLECTIONS_SHOULD_NOT_CONTAIN_THEMSELVES)</a></h3>
<p> This call to a generic collection's method would only make sense if a collection contained
itself (e.g., if <code>s.contains(s)</code> were true). This is unlikely to be true and would cause
problems if it were true (such as the computation of the hash code resulting in infinite recursion).
It is likely that the wrong value is being passed as a parameter.
</p>
<h3><a name="DMI_DOH">DMI: D'oh! A nonsensical method invocation (DMI_DOH)</a></h3>
<p>
This partical method invocation doesn't make sense, for reasons that should be apparent from inspection.
</p>
<h3><a name="DMI_INVOKING_HASHCODE_ON_ARRAY">DMI: Invocation of hashCode on an array (DMI_INVOKING_HASHCODE_ON_ARRAY)</a></h3>
<p>
The code invokes hashCode on an array. Calling hashCode on
an array returns the same value as System.identityHashCode, and ingores
the contents and length of the array. If you need a hashCode that
depends on the contents of an array <code>a</code>,
use <code>java.util.Arrays.hashCode(a)</code>.
</p>
<h3><a name="DMI_LONG_BITS_TO_DOUBLE_INVOKED_ON_INT">DMI: Double.longBitsToDouble invoked on an int (DMI_LONG_BITS_TO_DOUBLE_INVOKED_ON_INT)</a></h3>
<p> The Double.longBitsToDouble method is invoked, but a 32 bit int value is passed
as an argument. This almostly certainly is not intended and is unlikely
to give the intended result.
</p>
<h3><a name="DMI_VACUOUS_SELF_COLLECTION_CALL">DMI: Vacuous call to collections (DMI_VACUOUS_SELF_COLLECTION_CALL)</a></h3>
<p> This call doesn't make sense. For any collection <code>c</code>, calling <code>c.containsAll(c)</code> should
always be true, and <code>c.retainAll(c)</code> should have no effect.
</p>
<h3><a name="DMI_ANNOTATION_IS_NOT_VISIBLE_TO_REFLECTION">Dm: Can't use reflection to check for presence of annotation without runtime retention (DMI_ANNOTATION_IS_NOT_VISIBLE_TO_REFLECTION)</a></h3>
<p> Unless an annotation has itself been annotated with @Retention(RetentionPolicy.RUNTIME), the annotation can't be observed using reflection
(e.g., by using the isAnnotationPresent method).
.</p>
<h3><a name="DMI_FUTILE_ATTEMPT_TO_CHANGE_MAXPOOL_SIZE_OF_SCHEDULED_THREAD_POOL_EXECUTOR">Dm: Futile attempt to change max pool size of ScheduledThreadPoolExecutor (DMI_FUTILE_ATTEMPT_TO_CHANGE_MAXPOOL_SIZE_OF_SCHEDULED_THREAD_POOL_EXECUTOR)</a></h3>
<p>(<a href="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ScheduledThreadPoolExecutor.html">Javadoc</a>)
While ScheduledThreadPoolExecutor inherits from ThreadPoolExecutor, a few of the inherited tuning methods are not useful for it. In particular, because it acts as a fixed-sized pool using corePoolSize threads and an unbounded queue, adjustments to maximumPoolSize have no useful effect.
</p>
<h3><a name="DMI_SCHEDULED_THREAD_POOL_EXECUTOR_WITH_ZERO_CORE_THREADS">Dm: Creation of ScheduledThreadPoolExecutor with zero core threads (DMI_SCHEDULED_THREAD_POOL_EXECUTOR_WITH_ZERO_CORE_THREADS)</a></h3>
<p>(<a href="http://java.sun.com/javase/6/docs/api/java/util/concurrent/ScheduledThreadPoolExecutor.html#ScheduledThreadPoolExecutor(int)">Javadoc</a>)
A ScheduledThreadPoolExecutor with zero core threads will never execute anything; changes to the max pool size are ignored.
</p>
<h3><a name="DMI_VACUOUS_CALL_TO_EASYMOCK_METHOD">Dm: Useless/vacuous call to EasyMock method (DMI_VACUOUS_CALL_TO_EASYMOCK_METHOD)</a></h3>
<p>This call doesn't pass any objects to the EasyMock method, so the call doesn't do anything.
</p>
<h3><a name="EC_ARRAY_AND_NONARRAY">EC: equals() used to compare array and nonarray (EC_ARRAY_AND_NONARRAY)</a></h3>
<p>
This method invokes the .equals(Object o) to compare an array and a reference that doesn't seem
to be an array. If things being compared are of different types, they are guaranteed to be unequal
and the comparison is almost certainly an error. Even if they are both arrays, the equals method
on arrays only determines of the two arrays are the same object.
To compare the
contents of the arrays, use java.util.Arrays.equals(Object[], Object[]).
</p>
<h3><a name="EC_BAD_ARRAY_COMPARE">EC: Invocation of equals() on an array, which is equivalent to == (EC_BAD_ARRAY_COMPARE)</a></h3>
<p>
This method invokes the .equals(Object o) method on an array. Since arrays do not override the equals
method of Object, calling equals on an array is the same as comparing their addresses. To compare the
contents of the arrays, use <code>java.util.Arrays.equals(Object[], Object[])</code>.
To compare the addresses of the arrays, it would be
less confusing to explicitly check pointer equality using <code>==</code>.
</p>
<h3><a name="EC_INCOMPATIBLE_ARRAY_COMPARE">EC: equals(...) used to compare incompatible arrays (EC_INCOMPATIBLE_ARRAY_COMPARE)</a></h3>
<p>
This method invokes the .equals(Object o) to compare two arrays, but the arrays of
of incompatible types (e.g., String[] and StringBuffer[], or String[] and int[]).
They will never be equal. In addition, when equals(...) is used to compare arrays it
only checks to see if they are the same array, and ignores the contents of the arrays.
</p>
<h3><a name="EC_NULL_ARG">EC: Call to equals(null) (EC_NULL_ARG)</a></h3>
<p> This method calls equals(Object), passing a null value as
the argument. According to the contract of the equals() method,
this call should always return <code>false</code>.</p>
<h3><a name="EC_UNRELATED_CLASS_AND_INTERFACE">EC: Call to equals() comparing unrelated class and interface (EC_UNRELATED_CLASS_AND_INTERFACE)</a></h3>
<p>
This method calls equals(Object) on two references, one of which is a class
and the other an interface, where neither the class nor any of its
non-abstract subclasses implement the interface.
Therefore, the objects being compared
are unlikely to be members of the same class at runtime
(unless some application classes were not analyzed, or dynamic class
loading can occur at runtime).
According to the contract of equals(),
objects of different
classes should always compare as unequal; therefore, according to the
contract defined by java.lang.Object.equals(Object),
the result of this comparison will always be false at runtime.
</p>
<h3><a name="EC_UNRELATED_INTERFACES">EC: Call to equals() comparing different interface types (EC_UNRELATED_INTERFACES)</a></h3>
<p> This method calls equals(Object) on two references of unrelated
interface types, where neither is a subtype of the other,
and there are no known non-abstract classes which implement both interfaces.
Therefore, the objects being compared
are unlikely to be members of the same class at runtime
(unless some application classes were not analyzed, or dynamic class
loading can occur at runtime).
According to the contract of equals(),
objects of different
classes should always compare as unequal; therefore, according to the
contract defined by java.lang.Object.equals(Object),
the result of this comparison will always be false at runtime.
</p>
<h3><a name="EC_UNRELATED_TYPES">EC: Call to equals() comparing different types (EC_UNRELATED_TYPES)</a></h3>
<p> This method calls equals(Object) on two references of different
class types with no common subclasses.
Therefore, the objects being compared
are unlikely to be members of the same class at runtime
(unless some application classes were not analyzed, or dynamic class
loading can occur at runtime).
According to the contract of equals(),
objects of different
classes should always compare as unequal; therefore, according to the
contract defined by java.lang.Object.equals(Object),
the result of this comparison will always be false at runtime.
</p>
<h3><a name="EC_UNRELATED_TYPES_USING_POINTER_EQUALITY">EC: Using pointer equality to compare different types (EC_UNRELATED_TYPES_USING_POINTER_EQUALITY)</a></h3>
<p> This method uses using pointer equality to compare two references that seem to be of
different types. The result of this comparison will always be false at runtime.
</p>
<h3><a name="EQ_ALWAYS_FALSE">Eq: equals method always returns false (EQ_ALWAYS_FALSE)</a></h3>
<p> This class defines an equals method that always returns false. This means that an object is not equal to itself, and it is impossible to create useful Maps or Sets of this class. More fundamentally, it means
that equals is not reflexive, one of the requirements of the equals method.</p>
<p>The likely intended semantics are object identity: that an object is equal to itself. This is the behavior inherited from class <code>Object</code>. If you need to override an equals inherited from a different
superclass, you can use use:
<pre>
public boolean equals(Object o) { return this == o; }
</pre>
</p>
<h3><a name="EQ_ALWAYS_TRUE">Eq: equals method always returns true (EQ_ALWAYS_TRUE)</a></h3>
<p> This class defines an equals method that always returns true. This is imaginative, but not very smart.
Plus, it means that the equals method is not symmetric.
</p>
<h3><a name="EQ_COMPARING_CLASS_NAMES">Eq: equals method compares class names rather than class objects (EQ_COMPARING_CLASS_NAMES)</a></h3>
<p> This method checks to see if two objects are the same class by checking to see if the names
of their classes are equal. You can have different classes with the same name if they are loaded by
different class loaders. Just check to see if the class objects are the same.
</p>
<h3><a name="EQ_DONT_DEFINE_EQUALS_FOR_ENUM">Eq: Covariant equals() method defined for enum (EQ_DONT_DEFINE_EQUALS_FOR_ENUM)</a></h3>
<p> This class defines an enumeration, and equality on enumerations are defined
using object identity. Defining a covariant equals method for an enumeration
value is exceptionally bad practice, since it would likely result
in having two different enumeration values that compare as equals using
the covariant enum method, and as not equal when compared normally.
Don't do it.
</p>
<h3><a name="EQ_OTHER_NO_OBJECT">Eq: equals() method defined that doesn't override equals(Object) (EQ_OTHER_NO_OBJECT)</a></h3>
<p> This class defines an <code>equals()</code>
method, that doesn't override the normal <code>equals(Object)</code> method
defined in the base <code>java.lang.Object</code> class.&nbsp; Instead, it
inherits an <code>equals(Object)</code> method from a superclass.
The class should probably define a <code>boolean equals(Object)</code> method.
</p>
<h3><a name="EQ_OTHER_USE_OBJECT">Eq: equals() method defined that doesn't override Object.equals(Object) (EQ_OTHER_USE_OBJECT)</a></h3>
<p> This class defines an <code>equals()</code>
method, that doesn't override the normal <code>equals(Object)</code> method
defined in the base <code>java.lang.Object</code> class.&nbsp;
The class should probably define a <code>boolean equals(Object)</code> method.
</p>
<h3><a name="EQ_OVERRIDING_EQUALS_NOT_SYMMETRIC">Eq: equals method overrides equals in superclass and may not be symmetric (EQ_OVERRIDING_EQUALS_NOT_SYMMETRIC)</a></h3>
<p> This class defines an equals method that overrides an equals method in a superclass. Both equals methods
methods use <code>instanceof</code> in the determination of whether two objects are equal. This is fraught with peril,
since it is important that the equals method is symmetrical (in other words, <code>a.equals(b) == b.equals(a)</code>).
If B is a subtype of A, and A's equals method checks that the argument is an instanceof A, and B's equals method
checks that the argument is an instanceof B, it is quite likely that the equivalence relation defined by these
methods is not symmetric.
</p>
<h3><a name="EQ_SELF_USE_OBJECT">Eq: Covariant equals() method defined, Object.equals(Object) inherited (EQ_SELF_USE_OBJECT)</a></h3>
<p> This class defines a covariant version of the <code>equals()</code>
method, but inherits the normal <code>equals(Object)</code> method
defined in the base <code>java.lang.Object</code> class.&nbsp;
The class should probably define a <code>boolean equals(Object)</code> method.
</p>
<h3><a name="FE_TEST_IF_EQUAL_TO_NOT_A_NUMBER">FE: Doomed test for equality to NaN (FE_TEST_IF_EQUAL_TO_NOT_A_NUMBER)</a></h3>
<p>
This code checks to see if a floating point value is equal to the special
Not A Number value (e.g., <code>if (x == Double.NaN)</code>). However,
because of the special semantics of <code>NaN</code>, no value
is equal to <code>Nan</code>, including <code>NaN</code>. Thus,
<code>x == Double.NaN</code> always evaluates to false.
To check to see if a value contained in <code>x</code>
is the special Not A Number value, use
<code>Double.isNaN(x)</code> (or <code>Float.isNaN(x)</code> if
<code>x</code> is floating point precision).
</p>
<h3><a name="VA_FORMAT_STRING_BAD_ARGUMENT">FS: Format string placeholder incompatible with passed argument (VA_FORMAT_STRING_BAD_ARGUMENT)</a></h3>
<p>
The format string placeholder is incompatible with the corresponding
argument. For example,
<code>
System.out.println("%d\n", "hello");
</code>
<p>The %d placeholder requires a numeric argument, but a string value is
passed instead.
A runtime exception will occur when
this statement is executed.
</p>
<h3><a name="VA_FORMAT_STRING_BAD_CONVERSION">FS: The type of a supplied argument doesn't match format specifier (VA_FORMAT_STRING_BAD_CONVERSION)</a></h3>
<p>
One of the arguments is uncompatible with the corresponding format string specifier.
As a result, this will generate a runtime exception when executed.
For example, <code>String.format("%d", "1")</code> will generate an exception, since
the String "1" is incompatible with the format specifier %d.
</p>
<h3><a name="VA_FORMAT_STRING_EXPECTED_MESSAGE_FORMAT_SUPPLIED">FS: MessageFormat supplied where printf style format expected (VA_FORMAT_STRING_EXPECTED_MESSAGE_FORMAT_SUPPLIED)</a></h3>
<p>
A method is called that expects a Java printf format string and a list of arguments.
However, the format string doesn't contain any format specifiers (e.g., %s) but
does contain message format elements (e.g., {0}). It is likely
that the code is supplying a MessageFormat string when a printf-style format string
is required. At runtime, all of the arguments will be ignored
and the format string will be returned exactly as provided without any formatting.
</p>
</p>
<h3><a name="VA_FORMAT_STRING_EXTRA_ARGUMENTS_PASSED">FS: More arguments are passed than are actually used in the format string (VA_FORMAT_STRING_EXTRA_ARGUMENTS_PASSED)</a></h3>
<p>
A format-string method with a variable number of arguments is called,
but more arguments are passed than are actually used by the format string.
This won't cause a runtime exception, but the code may be silently omitting
information that was intended to be included in the formatted string.
</p>
<h3><a name="VA_FORMAT_STRING_ILLEGAL">FS: Illegal format string (VA_FORMAT_STRING_ILLEGAL)</a></h3>
<p>
The format string is syntactically invalid,
and a runtime exception will occur when
this statement is executed.
</p>
<h3><a name="VA_FORMAT_STRING_MISSING_ARGUMENT">FS: Format string references missing argument (VA_FORMAT_STRING_MISSING_ARGUMENT)</a></h3>
<p>
Not enough arguments are passed to satisfy a placeholder in the format string.
A runtime exception will occur when
this statement is executed.
</p>
<h3><a name="VA_FORMAT_STRING_NO_PREVIOUS_ARGUMENT">FS: No previous argument for format string (VA_FORMAT_STRING_NO_PREVIOUS_ARGUMENT)</a></h3>
<p>
The format string specifies a relative index to request that the argument for the previous format specifier
be reused. However, there is no previous argument.
For example,
</p>
<p><code>formatter.format("%&lt;s %s", "a", "b")</code>
</p>
<p>would throw a MissingFormatArgumentException when executed.
</p>
<h3><a name="GC_UNRELATED_TYPES">GC: No relationship between generic parameter and method argument (GC_UNRELATED_TYPES)</a></h3>
<p> This call to a generic collection method contains an argument
with an incompatible class from that of the collection's parameter
(i.e., the type of the argument is neither a supertype nor a subtype
of the corresponding generic type argument).
Therefore, it is unlikely that the collection contains any objects
that are equal to the method argument used here.
Most likely, the wrong value is being passed to the method.</p>
<p>In general, instances of two unrelated classes are not equal.
For example, if the <code>Foo</code> and <code>Bar</code> classes
are not related by subtyping, then an instance of <code>Foo</code>
should not be equal to an instance of <code>Bar</code>.
Among other issues, doing so will likely result in an equals method
that is not symmetrical. For example, if you define the <code>Foo</code> class
so that a <code>Foo</code> can be equal to a <code>String</code>,
your equals method isn't symmetrical since a <code>String</code> can only be equal
to a <code>String</code>.
</p>
<p>In rare cases, people do define nonsymmetrical equals methods and still manage to make
their code work. Although none of the APIs document or guarantee it, it is typically
the case that if you check if a <code>Collection&lt;String&gt;</code> contains
a <code>Foo</code>, the equals method of argument (e.g., the equals method of the
<code>Foo</code> class) used to perform the equality checks.
</p>
<h3><a name="HE_SIGNATURE_DECLARES_HASHING_OF_UNHASHABLE_CLASS">HE: Signature declares use of unhashable class in hashed construct (HE_SIGNATURE_DECLARES_HASHING_OF_UNHASHABLE_CLASS)</a></h3>
<p> A method, field or class declares a generic signature where a non-hashable class
is used in context where a hashable class is required.
A class that declares an equals method but inherits a hashCode() method
from Object is unhashable, since it doesn't fulfill the requirement that
equal objects have equal hashCodes.
</p>
<h3><a name="HE_USE_OF_UNHASHABLE_CLASS">HE: Use of class without a hashCode() method in a hashed data structure (HE_USE_OF_UNHASHABLE_CLASS)</a></h3>
<p> A class defines an equals(Object) method but not a hashCode() method,
and thus doesn't fulfill the requirement that equal objects have equal hashCodes.
An instance of this class is used in a hash data structure, making the need to
fix this problem of highest importance.
<h3><a name="ICAST_INT_2_LONG_AS_INSTANT">ICAST: int value converted to long and used as absolute time (ICAST_INT_2_LONG_AS_INSTANT)</a></h3>
<p>
This code converts a 32-bit int value to a 64-bit long value, and then
passes that value for a method parameter that requires an absolute time value.
An absolute time value is the number
of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.
For example, the following method, intended to convert seconds since the epoc into a Date, is badly
broken:</p>
<pre>
Date getDate(int seconds) { return new Date(seconds * 1000); }
</pre>
<p>The multiplication is done using 32-bit arithmetic, and then converted to a 64-bit value.
When a 32-bit value is converted to 64-bits and used to express an absolute time
value, only dates in December 1969 and January 1970 can be represented.</p>
<p>Correct implementations for the above method are:</p>
<pre>
// Fails for dates after 2037
Date getDate(int seconds) { return new Date(seconds * 1000L); }
// better, works for all dates
Date getDate(long seconds) { return new Date(seconds * 1000); }
</pre>
<h3><a name="ICAST_INT_CAST_TO_DOUBLE_PASSED_TO_CEIL">ICAST: integral value cast to double and then passed to Math.ceil (ICAST_INT_CAST_TO_DOUBLE_PASSED_TO_CEIL)</a></h3>
<p>
This code converts an integral value (e.g., int or long)
to a double precision
floating point number and then
passing the result to the Math.ceil() function, which rounds a double to
the next higher integer value. This operation should always be a no-op,
since the converting an integer to a double should give a number with no fractional part.
It is likely that the operation that generated the value to be passed
to Math.ceil was intended to be performed using double precision
floating point arithmetic.
</p>
<h3><a name="ICAST_INT_CAST_TO_FLOAT_PASSED_TO_ROUND">ICAST: int value cast to float and then passed to Math.round (ICAST_INT_CAST_TO_FLOAT_PASSED_TO_ROUND)</a></h3>
<p>
This code converts an int value to a float precision
floating point number and then
passing the result to the Math.round() function, which returns the int/long closest
to the argument. This operation should always be a no-op,
since the converting an integer to a float should give a number with no fractional part.
It is likely that the operation that generated the value to be passed
to Math.round was intended to be performed using
floating point arithmetic.
</p>
<h3><a name="IJU_ASSERT_METHOD_INVOKED_FROM_RUN_METHOD">IJU: JUnit assertion in run method will not be noticed by JUnit (IJU_ASSERT_METHOD_INVOKED_FROM_RUN_METHOD)</a></h3>
<p> A JUnit assertion is performed in a run method. Failed JUnit assertions
just result in exceptions being thrown.
Thus, if this exception occurs in a thread other than the thread that invokes
the test method, the exception will terminate the thread but not result
in the test failing.
</p>
<h3><a name="IJU_BAD_SUITE_METHOD">IJU: TestCase declares a bad suite method (IJU_BAD_SUITE_METHOD)</a></h3>
<p> Class is a JUnit TestCase and defines a suite() method.
However, the suite method needs to be declared as either
<pre>public static junit.framework.Test suite()</pre>
or
<pre>public static junit.framework.TestSuite suite()</pre>
</p>
<h3><a name="IJU_NO_TESTS">IJU: TestCase has no tests (IJU_NO_TESTS)</a></h3>
<p> Class is a JUnit TestCase but has not implemented any test methods</p>
<h3><a name="IJU_SETUP_NO_SUPER">IJU: TestCase defines setUp that doesn't call super.setUp() (IJU_SETUP_NO_SUPER)</a></h3>
<p> Class is a JUnit TestCase and implements the setUp method. The setUp method should call
super.setUp(), but doesn't.</p>
<h3><a name="IJU_SUITE_NOT_STATIC">IJU: TestCase implements a non-static suite method (IJU_SUITE_NOT_STATIC)</a></h3>
<p> Class is a JUnit TestCase and implements the suite() method.
The suite method should be declared as being static, but isn't.</p>
<h3><a name="IJU_TEARDOWN_NO_SUPER">IJU: TestCase defines tearDown that doesn't call super.tearDown() (IJU_TEARDOWN_NO_SUPER)</a></h3>
<p> Class is a JUnit TestCase and implements the tearDown method. The tearDown method should call
super.tearDown(), but doesn't.</p>
<h3><a name="IL_CONTAINER_ADDED_TO_ITSELF">IL: A collection is added to itself (IL_CONTAINER_ADDED_TO_ITSELF)</a></h3>
<p>A collection is added to itself. As a result, computing the hashCode of this
set will throw a StackOverflowException.
</p>
<h3><a name="IL_INFINITE_LOOP">IL: An apparent infinite loop (IL_INFINITE_LOOP)</a></h3>
<p>This loop doesn't seem to have a way to terminate (other than by perhaps
throwing an exception).</p>
<h3><a name="IL_INFINITE_RECURSIVE_LOOP">IL: An apparent infinite recursive loop (IL_INFINITE_RECURSIVE_LOOP)</a></h3>
<p>This method unconditionally invokes itself. This would seem to indicate
an infinite recursive loop that will result in a stack overflow.</p>
<h3><a name="IM_MULTIPLYING_RESULT_OF_IREM">IM: Integer multiply of result of integer remainder (IM_MULTIPLYING_RESULT_OF_IREM)</a></h3>
<p>
The code multiplies the result of an integer remaining by an integer constant.
Be sure you don't have your operator precedence confused. For example
i % 60 * 1000 is (i % 60) * 1000, not i % (60 * 1000).
</p>
<h3><a name="INT_BAD_COMPARISON_WITH_INT_VALUE">INT: Bad comparison of int value with long constant (INT_BAD_COMPARISON_WITH_INT_VALUE)</a></h3>
<p> This code compares an int value with a long constant that is outside
the range of values that can be represented as an int value.
This comparison is vacuous and possibily to be incorrect.
</p>
<h3><a name="INT_BAD_COMPARISON_WITH_NONNEGATIVE_VALUE">INT: Bad comparison of nonnegative value with negative constant (INT_BAD_COMPARISON_WITH_NONNEGATIVE_VALUE)</a></h3>
<p> This code compares a value that is guaranteed to be non-negative with a negative constant.
</p>
<h3><a name="INT_BAD_COMPARISON_WITH_SIGNED_BYTE">INT: Bad comparison of signed byte (INT_BAD_COMPARISON_WITH_SIGNED_BYTE)</a></h3>
<p> Signed bytes can only have a value in the range -128 to 127. Comparing
a signed byte with a value outside that range is vacuous and likely to be incorrect.
To convert a signed byte <code>b</code> to an unsigned value in the range 0..255,
use <code>0xff &amp; b</code>
</p>
<h3><a name="IO_APPENDING_TO_OBJECT_OUTPUT_STREAM">IO: Doomed attempt to append to an object output stream (IO_APPENDING_TO_OBJECT_OUTPUT_STREAM)</a></h3>
<p>
This code opens a file in append mode and then wraps the result in an object output stream.
This won't allow you to append to an existing object output stream stored in a file. If you want to be
able to append to an object output stream, you need to keep the object output stream open.
</p>
<p>The only situation in which opening a file in append mode and the writing an object output stream
could work is if on reading the file you plan to open it in random access mode and seek to the byte offset
where the append started.
</p>
<p>
TODO: example.
</p>
<h3><a name="IP_PARAMETER_IS_DEAD_BUT_OVERWRITTEN">IP: A parameter is dead upon entry to a method but overwritten (IP_PARAMETER_IS_DEAD_BUT_OVERWRITTEN)</a></h3>
<p>
The initial value of this parameter is ignored, and the parameter
is overwritten here. This often indicates a mistaken belief that
the write to the parameter will be conveyed back to
the caller.
</p>
<h3><a name="MF_CLASS_MASKS_FIELD">MF: Class defines field that masks a superclass field (MF_CLASS_MASKS_FIELD)</a></h3>
<p> This class defines a field with the same name as a visible
instance field in a superclass. This is confusing, and
may indicate an error if methods update or access one of
the fields when they wanted the other.</p>
<h3><a name="MF_METHOD_MASKS_FIELD">MF: Method defines a variable that obscures a field (MF_METHOD_MASKS_FIELD)</a></h3>
<p> This method defines a local variable with the same name as a field
in this class or a superclass. This may cause the method to
read an uninitialized value from the field, leave the field uninitialized,
or both.</p>
<h3><a name="NP_ALWAYS_NULL">NP: Null pointer dereference (NP_ALWAYS_NULL)</a></h3>
<p> A null pointer is dereferenced here.&nbsp; This will lead to a
<code>NullPointerException</code> when the code is executed.</p>
<h3><a name="NP_ALWAYS_NULL_EXCEPTION">NP: Null pointer dereference in method on exception path (NP_ALWAYS_NULL_EXCEPTION)</a></h3>
<p> A pointer which is null on an exception path is dereferenced here.&nbsp;
This will lead to a <code>NullPointerException</code> when the code is executed.&nbsp;
Note that because FindBugs currently does not prune infeasible exception paths,
this may be a false warning.</p>
<p> Also note that FindBugs considers the default case of a switch statement to
be an exception path, since the default case is often infeasible.</p>
<h3><a name="NP_ARGUMENT_MIGHT_BE_NULL">NP: Method does not check for null argument (NP_ARGUMENT_MIGHT_BE_NULL)</a></h3>
<p>
A parameter to this method has been identified as a value that should
always be checked to see whether or not it is null, but it is being dereferenced
without a preceding null check.
</p>
<h3><a name="NP_CLOSING_NULL">NP: close() invoked on a value that is always null (NP_CLOSING_NULL)</a></h3>
<p> close() is being invoked on a value that is always null. If this statement is executed,
a null pointer exception will occur. But the big risk here you never close
something that should be closed.
<h3><a name="NP_GUARANTEED_DEREF">NP: Null value is guaranteed to be dereferenced (NP_GUARANTEED_DEREF)</a></h3>
<p>
There is a statement or branch that if executed guarantees that
a value is null at this point, and that
value that is guaranteed to be dereferenced
(except on forward paths involving runtime exceptions).
</p>
<p>Note that a check such as
<code>if (x == null) throw new NullPointerException();</code
is treated as a dereference of <code>x</code>.
<h3><a name="NP_GUARANTEED_DEREF_ON_EXCEPTION_PATH">NP: Value is null and guaranteed to be dereferenced on exception path (NP_GUARANTEED_DEREF_ON_EXCEPTION_PATH)</a></h3>
<p>
There is a statement or branch on an exception path
that if executed guarantees that
a value is null at this point, and that
value that is guaranteed to be dereferenced
(except on forward paths involving runtime exceptions).
</p>
<h3><a name="NP_NONNULL_FIELD_NOT_INITIALIZED_IN_CONSTRUCTOR">NP: Nonnull field is not initialized (NP_NONNULL_FIELD_NOT_INITIALIZED_IN_CONSTRUCTOR)</a></h3>
<p> The field is marked as nonnull, but isn't written to by the constructor.
The field might be initialized elsewhere during constructor, or might always
be initialized before use.
</p>
<h3><a name="NP_NONNULL_PARAM_VIOLATION">NP: Method call passes null to a nonnull parameter (NP_NONNULL_PARAM_VIOLATION)</a></h3>
<p>
This method passes a null value as the parameter of a method which
must be nonnull. Either this parameter has been explicitly marked
as @Nonnull, or analysis has determined that this parameter is
always dereferenced.
</p>
<h3><a name="NP_NONNULL_RETURN_VIOLATION">NP: Method may return null, but is declared @NonNull (NP_NONNULL_RETURN_VIOLATION)</a></h3>
<p>
This method may return a null value, but the method (or a superclass method
which it overrides) is declared to return @NonNull.
</p>
<h3><a name="NP_NULL_INSTANCEOF">NP: A known null value is checked to see if it is an instance of a type (NP_NULL_INSTANCEOF)</a></h3>
<p>
This instanceof test will always return false, since the value being checked is guaranteed to be null.
Although this is safe, make sure it isn't
an indication of some misunderstanding or some other logic error.
</p>
<h3><a name="NP_NULL_ON_SOME_PATH">NP: Possible null pointer dereference (NP_NULL_ON_SOME_PATH)</a></h3>
<p> There is a branch of statement that, <em>if executed,</em> guarantees that
a null value will be dereferenced, which
would generate a <code>NullPointerException</code> when the code is executed.
Of course, the problem might be that the branch or statement is infeasible and that
the null pointer exception can't ever be executed; deciding that is beyond the ability of FindBugs.
</p>
<h3><a name="NP_NULL_ON_SOME_PATH_EXCEPTION">NP: Possible null pointer dereference in method on exception path (NP_NULL_ON_SOME_PATH_EXCEPTION)</a></h3>
<p> A reference value which is null on some exception control path is
dereferenced here.&nbsp; This may lead to a <code>NullPointerException</code>
when the code is executed.&nbsp;
Note that because FindBugs currently does not prune infeasible exception paths,
this may be a false warning.</p>
<p> Also note that FindBugs considers the default case of a switch statement to
be an exception path, since the default case is often infeasible.</p>
<h3><a name="NP_NULL_PARAM_DEREF">NP: Method call passes null for nonnull parameter (NP_NULL_PARAM_DEREF)</a></h3>
<p>
This method call passes a null value for a nonnull method parameter.
Either the parameter is annotated as a parameter that should
always be nonnull, or analysis has shown that it will always be
dereferenced.
</p>
<h3><a name="NP_NULL_PARAM_DEREF_ALL_TARGETS_DANGEROUS">NP: Method call passes null for nonnull parameter (NP_NULL_PARAM_DEREF_ALL_TARGETS_DANGEROUS)</a></h3>
<p>
A possibly-null value is passed at a call site where all known
target methods require the parameter to be nonnull.
Either the parameter is annotated as a parameter that should
always be nonnull, or analysis has shown that it will always be
dereferenced.
</p>
<h3><a name="NP_NULL_PARAM_DEREF_NONVIRTUAL">NP: Non-virtual method call passes null for nonnull parameter (NP_NULL_PARAM_DEREF_NONVIRTUAL)</a></h3>
<p>
A possibly-null value is passed to a nonnull method parameter.
Either the parameter is annotated as a parameter that should
always be nonnull, or analysis has shown that it will always be
dereferenced.
</p>
<h3><a name="NP_STORE_INTO_NONNULL_FIELD">NP: Store of null value into field annotated NonNull (NP_STORE_INTO_NONNULL_FIELD)</a></h3>
<p> A value that could be null is stored into a field that has been annotated as NonNull. </p>
<h3><a name="NP_UNWRITTEN_FIELD">NP: Read of unwritten field (NP_UNWRITTEN_FIELD)</a></h3>
<p> The program is dereferencing a field that does not seem to ever have a non-null value written to it.
Unless the field is initialized via some mechanism not seen by the analysis,
dereferencing this value will generate a null pointer exception.
</p>
<h3><a name="NM_BAD_EQUAL">Nm: Class defines equal(Object); should it be equals(Object)? (NM_BAD_EQUAL)</a></h3>
<p> This class defines a method <code>equal(Object)</code>.&nbsp; This method does
not override the <code>equals(Object)</code> method in <code>java.lang.Object</code>,
which is probably what was intended.</p>
<h3><a name="NM_LCASE_HASHCODE">Nm: Class defines hashcode(); should it be hashCode()? (NM_LCASE_HASHCODE)</a></h3>
<p> This class defines a method called <code>hashcode()</code>.&nbsp; This method
does not override the <code>hashCode()</code> method in <code>java.lang.Object</code>,
which is probably what was intended.</p>
<h3><a name="NM_LCASE_TOSTRING">Nm: Class defines tostring(); should it be toString()? (NM_LCASE_TOSTRING)</a></h3>
<p> This class defines a method called <code>tostring()</code>.&nbsp; This method
does not override the <code>toString()</code> method in <code>java.lang.Object</code>,
which is probably what was intended.</p>
<h3><a name="NM_METHOD_CONSTRUCTOR_CONFUSION">Nm: Apparent method/constructor confusion (NM_METHOD_CONSTRUCTOR_CONFUSION)</a></h3>
<p> This regular method has the same name as the class it is defined in. It is likely that this was intended to be a constructor.
If it was intended to be a constructor, remove the declaration of a void return value.
If you had accidently defined this method, realized the mistake, defined a proper constructor
but can't get rid of this method due to backwards compatibility, deprecate the method.
</p>
<h3><a name="NM_VERY_CONFUSING">Nm: Very confusing method names (NM_VERY_CONFUSING)</a></h3>
<p> The referenced methods have names that differ only by capitalization.
This is very confusing because if the capitalization were
identical then one of the methods would override the other.
</p>
<h3><a name="NM_WRONG_PACKAGE">Nm: Method doesn't override method in superclass due to wrong package for parameter (NM_WRONG_PACKAGE)</a></h3>
<p> The method in the subclass doesn't override a similar method in a superclass because the type of a parameter doesn't exactly match
the type of the corresponding parameter in the superclass. For example, if you have:</p>
<blockquote>
<pre>
import alpha.Foo;
public class A {
public int f(Foo x) { return 17; }
}
----
import beta.Foo;
public class B extends A {
public int f(Foo x) { return 42; }
}
</pre>
</blockquote>
<p>The <code>f(Foo)</code> method defined in class <code>B</code> doesn't
override the
<code>f(Foo)</code> method defined in class <code>A</code>, because the argument
types are <code>Foo</code>'s from different packages.
</p>
<h3><a name="QBA_QUESTIONABLE_BOOLEAN_ASSIGNMENT">QBA: Method assigns boolean literal in boolean expression (QBA_QUESTIONABLE_BOOLEAN_ASSIGNMENT)</a></h3>
<p>
This method assigns a literal boolean value (true or false) to a boolean variable inside
an if or while expression. Most probably this was supposed to be a boolean comparison using
==, not an assignment using =.
</p>
<h3><a name="RC_REF_COMPARISON">RC: Suspicious reference comparison (RC_REF_COMPARISON)</a></h3>