Annotation Interface Nullable

@Documented @Target({FIELD,METHOD,PARAMETER,LOCAL_VARIABLE}) @Retention(CLASS) @Nonnull(when=UNKNOWN) @TypeQualifierNickname public @interface Nullable
The annotated element could be null under some circumstances. In general, this means developers will have to read the documentation to determine when a null value is acceptable and whether it is necessary to check for a null value. When this annotation is applied to a method it applies to the method return value.