}

    // reference queues, for garbage collection cleanup

    /** Cleanup collected entries when the lock is available. */
    void tryDrainReferenceQueues() {
      if (tryLock()) {
        try {
          maybeDrainReferenceQueues();
        } finally {
          unlock();
        }
      }
    }

    @GuardedBy("this")

   * {@code tailSet} views.
   *
   * <pre>{@code
   * NavigableSet<E> set = synchronizedNavigableSet(new TreeSet<E>());
   *  ...
   * synchronized (set) {
   *   // Must be in the synchronized block
   *   Iterator<E> it = set.iterator();
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }</pre>
   *
   * <p>or:
   *
   * <pre>{@code

         * the Transport thread is not setup until doConnect()
         * returns and we want to suppress all communication
         * until we have properly negotiated.
         */
        synchronized ( this.inLock ) {
            if ( prt == 139 ) {
                ssn139();
            }
            else {
                if ( prt == 0 )
                    prt = DEFAULT_PORT; // 445