src/main/java/org/jboss/util/collection/WeakSet.java
protected final void maintain() {
      WeakObject weak;
      while ((weak = (WeakObject)queue.poll()) != null) {
         set.remove(weak);
      }
   }
protected final void maintain() {
      WeakObject weak;
      while ((weak = (WeakObject)queue.poll()) != null) {
         set.remove(weak);
      }
   }
Maintain the elements in the set.  Removes objects from the set that
have been reclaimed due to GC.