src/share/classes/java/lang/ref/Reference.java

*** 87,97 ****
       * field is also used for linking Reference objects in the pending list.
       */
  
      private T referent;         /* Treated specially by GC */
  
!     ReferenceQueue<? super T> queue;
  
      /* When active:   NULL
       *     pending:   this
       *    Enqueued:   next reference in queue (or this if last)
       *    Inactive:   this
--- 87,97 ----
       * field is also used for linking Reference objects in the pending list.
       */
  
      private T referent;         /* Treated specially by GC */
  
!     volatile ReferenceQueue<? super T> queue;
  
      /* When active:   NULL
       *     pending:   this
       *    Enqueued:   next reference in queue (or this if last)
       *    Inactive:   this
*** 223,235 ****
       *
       * @return   <code>true</code> if and only if this reference object has
       *           been enqueued
       */
      public boolean isEnqueued() {
!         synchronized (this) {
!             return (this.next != null && this.queue == ReferenceQueue.ENQUEUED);
!         }
      }
  
      /**
       * Adds this reference object to the queue with which it is registered,
       * if any.
--- 223,233 ----
       *
       * @return   <code>true</code> if and only if this reference object has
       *           been enqueued
       */
      public boolean isEnqueued() {
!         return (this.queue == ReferenceQueue.ENQUEUED);
      }
  
      /**
       * Adds this reference object to the queue with which it is registered,
       * if any.