```
@Documented
@Retention(RUNTIME)
@Target({TYPE_USE,TYPE_PARAMETER})
@SubtypeOf(MaybeAliased.class)
public @interface Unique
```
An expression with this type has no aliases. In other words, no other expression, evaluated at the same program point, would evaluate to the exact same object value.
A constructor's return type should be annotated with @Unique if the constructor does not leak references to the constructed object. For example, the String() constructor return type is annotated as @Unique.

See Also:

MaybeAliased

See the Checker Framework Manual:
Aliasing Checker

Annotation Type Unique