| Package | Description | 
|---|---|
| java.lang.ref | Provides reference-object classes, which support a limited degree of
interaction with the garbage collector. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | PhantomReference<T>Phantom reference objects, which are enqueued after the collector
 determines that their referents may otherwise be reclaimed. | 
| class  | SoftReference<T>Soft reference objects, which are cleared at the discretion of the garbage
 collector in response to memory demand. | 
| class  | WeakReference<T>Weak reference objects, which do not prevent their referents from being
 made finalizable, finalized, and then reclaimed. | 
| Modifier and Type | Method and Description | 
|---|---|
| Reference<? extends T> | ReferenceQueue. poll()Polls this queue to see if a reference object is available. | 
| Reference<? extends T> | ReferenceQueue. remove()Removes the next reference object in this queue, blocking until one
 becomes available. | 
| Reference<? extends T> | ReferenceQueue. remove(long timeout)Removes the next reference object in this queue, blocking until either
 one becomes available or the given timeout period expires. | 
 Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
 Copyright © 1993, 2015, Oracle and/or its affiliates.  All rights reserved.