| Annotation Type | Description | 
|---|---|
| NonNull | Indicates that a field, local variable, method return value or parameter can never be  null. | 
| NonNullByDefault | Indicates that all fields, method return values or parameters can never be  nullin the annotated package
 or type. | 
| Nullable | Indicates that a field, local variable, method return value or parameter can be  null. | 
null analysis.