org.vmmagic
Annotation Type Unboxed

@Retention(value=RUNTIME)
@Target(value=TYPE)
@Inherited
public @interface Unboxed

The Unboxed annotation marks a type as unboxed. Besides the primitive types, all Java values are boxed types. Conceptually, they are represented by a pointer to a heap object. However, an unboxed type is represented by the value itself. All methods on an unboxed type are Intrinsics.

As an unboxed type is not a regular java object there are a few constraints on the way unboxed types are handled;

• All methods are Intrinsic and thus there can be no virtual methods.
• An unboxed type can not be synchronized on.
• An unboxed type has no hashcode.
• An unboxed type MUST NOT be passed where an object is expected or when two overloaded methods can only be distinguished by by Object vs unboxed parameter type.

NOTE: At the current time the Unboxed annotation is only used for documentation purposes but in the near future it is expected that the semantics of the annotation will be enforced by the compiler.