code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.concurrent.locks.ReentrantLock;
  
  /*
   * Written by Doug Lea with assistance from members of JCP JSR-166
   * Expert Group and released to the public domain, as explained at
   * http://creativecommons.org/licenses/publicdomain
   */
  
  /*
   * @test
   * @bug 4486658
   * @compile -source 1.5 CancelledLockLoops.java
   * @run main/timeout=2800 CancelledLockLoops
   * @summary tests lockInterruptibly.
   * Checks for responsiveness of locks to interrupts. Runs under that
   * assumption that ITERS_VALUE computations require more than TIMEOUT
   * msecs to complete.
   */
  
  import java.util.concurrent.*;
  import java.util.concurrent.locks.*;
  import java.util.*;
  
  public final class CancelledLockLoops {
      static final Random rng = new Random();
      static boolean print = false;
      static final int ITERS = 1000000;
      static final long TIMEOUT = 100;
  
      public static void main(String[] args) throws Exception {
          int maxThreads = 5;
          if (args.length > 0)
              maxThreads = Integer.parseInt(args[0]);
  
          print = true;
  
          for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
              System.out.print("Threads: " + i);
              try {
                  new ReentrantLockLoop(i).test();
              }
              catch(BrokenBarrierException bb) {
                  // OK, ignore
              }
              Thread.sleep(TIMEOUT);
          }
      }
  
      static final class ReentrantLockLoop implements Runnable {
          private int v = rng.nextInt();
          private int completed;
          private volatile int result = 17;
          private final ReentrantLock lock = new ReentrantLock();
          private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
          private final CyclicBarrier barrier;
          private final int nthreads;
          ReentrantLockLoop(int nthreads) {
              this.nthreads = nthreads;
              barrier = new CyclicBarrier(nthreads+1, timer);
          }
  
          final void test() throws Exception {
              Thread[] threads = new Thread[nthreads];
              for (int i = 0; i < threads.length; ++i)
                  threads[i] = new Thread(this);
              for (int i = 0; i < threads.length; ++i)
                  threads[i].start();
              Thread[] cancels = (Thread[]) (threads.clone());
              Collections.shuffle(Arrays.asList(cancels), rng);
              barrier.await();
              Thread.sleep(TIMEOUT);
              for (int i = 0; i < cancels.length-2; ++i) {
                  cancels[i].interrupt();
                  // make sure all OK even when cancellations spaced out
                  if ( (i & 3) == 0)
                      Thread.sleep(1 + rng.nextInt(10));
              }
              barrier.await();
              if (print) {
                  long time = timer.getTime();
                  double secs = (double)(time) / 1000000000.0;
                  System.out.println("\t " + secs + "s run time");
              }
  
              int c;
              lock.lock();
              try {
                  c = completed;
              }
              finally {
                  lock.unlock();
              }
              if (c != 2)
                  throw new Error("Completed != 2");
              int r = result;
              if (r == 0) // avoid overoptimization
                  System.out.println("useless result: " + r);
          }
  
          public final void run() {
              try {
                  barrier.await();
                  int sum = v;
                  int x = 0;
                  int n = ITERS;
                  boolean done = false;
                  do {
                      try {
                          lock.lockInterruptibly();
                      }
                      catch (InterruptedException ie) {
                          break;
                      }
                      try {
                          v = x = LoopHelpers.compute1(v);
                      }
                      finally {
                          lock.unlock();
                      }
                      sum += LoopHelpers.compute2(x);
                  } while (n-- > 0);
                  if (n <= 0) {
                      lock.lock();
                      try {
                          ++completed;
                      }
                      finally {
                          lock.unlock();
                      }
                  }
                  barrier.await();
                  result += sum;
              }
              catch (Exception ex) {
                  ex.printStackTrace();
                  return;
              }
          }
      }
  
  }
  