import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible
public class MonitorBasedPriorityBlockingQueue<E> extends AbstractQueue<E>
    implements BlockingQueue<E> {

  // Based on revision 1.55 of PriorityBlockingQueue by Doug Lea, from
  // http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/main/java/util/concurrent/

  private static final long serialVersionUID = 5595510919245408276L;

  final PriorityQueue<E> q;