```
@Retention(CLASS)
public @interface InternalAPI
```
Anything annotated with this Annotation is considered internal API and should only be used if you know what you do.

Type:
If annotating a type (Class) the class itself is internal you should not implement or extend it. It does not say anything about the methods defined in this Class.

Methods:
If annotating a method the method is considered internal API. Checks and security measurements are omitted in these and the Method signature or implementation can change each and every version.

Fields:
If annotating a field the field should not be used from anywhere. It is public because it speeds up something or makes something easier to use.

Annotation Type InternalAPI