Checks if @NullMarked annotation is applied to a Java class.

When you apply @NullMarked to a module, package, class, or method, it means that unannotated types in that scope are treated as if they were annotated with @NonNull, with some exceptions for local variables and type variables. In code covered by @NullMarked, String x means the same as @NonNull String x.

This standardizes the default annotation for all static checkers and compilers that support JSpecify annotations.

For more information, see https://jspecify.dev/docs/user-guide/#nullmarked.

Choice of Granularity

Typically, projects should choose only one of the following approaches and not both:

• Package-level (AddNullMarkedToPackageInfo): Provides a concise way to null-mark an entire package at once. However, there are some drawbacks to relying on package-info.java in certain build environments, and it may lack the “locality of reference” provided by class-level annotations.
• Class-level (AddNullMarkedToClass): More robust and explicit, as the annotation is visible directly on each class declaration. This requires more annotations but can be clearer for readers.

For a project, it is recommended to either nullmark all the classes or all of the package-info files, but not both.