Java compact1, compact2, compact3 java.lang.ref Class Reference<T>（JDK8）

Method Detail

• get

  public T get()

  Returns this reference object's referent. If this reference object has been cleared, either by the program or by the garbage collector, then this method returns null.

  Returns:

  The object to which this reference refers, or null if this reference object has been cleared

• clear

  public void clear()

  Clears this reference object. Invoking this method will not cause this object to be enqueued.

  This method is invoked only by Java code; when the garbage collector clears references it does so directly, without invoking this method.

• isEnqueued

  public boolean isEnqueued()

  Tells whether or not this reference object has been enqueued, either by the program or by the garbage collector. If this reference object was not registered with a queue when it was created, then this method will always return false.

  Returns:

  true if and only if this reference object has been enqueued

• enqueue

  public boolean enqueue()

  Clears this reference object and adds it to the queue with which it is registered, if any.

  This method is invoked only by Java code; when the garbage collector enqueues references it does so directly, without invoking this method.

  Returns:

  true if this reference object was successfully enqueued; false if it was already enqueued or if it was not registered with a queue when it was created

• clone

  protected Object clone()
                  throws CloneNotSupportedException

  Throws CloneNotSupportedException. A Reference cannot be meaningfully cloned. Construct a new Reference instead.

  Overrides:

  clone in class Object

  API Note:

  This method is defined in Java SE 8 Maintenance Release 4.

  Returns:

  never returns normally

  Throws:

  CloneNotSupportedException - always

  Since:

  8

  See Also:

  Cloneable