# All Classes and Interfaces

Annotation Interfaces
Class
Description
NonNull
Indicates that the annotated type usage (commonly a parameter type or return type) is considered to exclude `null` as a value; rarely needed within null-marked code.
Nullable
Indicates that the annotated type usage (commonly a parameter type or return type) is considered to include `null` as a value.
NullMarked
Indicates that the annotated element and the code transitively enclosed within it are null-marked code: there, type usages are generally considered to exclude `null` as a value unless specified otherwise.
NullUnmarked
Indicates that the annotated element and the code transitively enclosed within it is null-unmarked code: there, type usages generally have unspecified nullness unless explicitly annotated otherwise.