ClassKey

```
@Documented
@Target({METHOD,FIELD,TYPE})
@Retention(RUNTIME)
@MapKey
public @interface ClassKey
```
A MapKey annotation for maps with Class<?> keys.
If your map's keys can be constrained, consider using a custom annotation instead, with a member whose type is Class<? extends Something>.

- Required Element Summary
  
  Required Elements
  Modifier and Type Required Element Description
  
  java.lang.Class<?> value

- Element Detail
  - value
```
java.lang.Class<?> value
```