| 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.