code: // from gee.cs.oswego.edu/home/jsr166/jsr166
  
  package jsr166tests.jtreg.util.concurrent.ScheduledThreadPoolExecutor;
  
  /*
   * 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 6725789
   * @summary Check for long overflow in task time comparison.
   */
  
  import java.util.concurrent.*;
  
  public class DelayOverflow {
      static void waitForNanoTimeTick() {
          for (long t0 = System.nanoTime(); t0 == System.nanoTime(); )
              ;
      }
  
      void scheduleNow(ScheduledThreadPoolExecutor pool,
                       Runnable r, int how) {
          switch (how) {
          case 0:
              pool.schedule(r, 0, TimeUnit.MILLISECONDS);
              break;
          case 1:
              pool.schedule(Executors.callable(r), 0, TimeUnit.DAYS);
              break;
          case 2:
              pool.scheduleWithFixedDelay(r, 0, 1000, TimeUnit.NANOSECONDS);
              break;
          case 3:
              pool.scheduleAtFixedRate(r, 0, 1000, TimeUnit.MILLISECONDS);
              break;
          default:
              fail(String.valueOf(how));
          }
      }
  
      void scheduleAtTheEndOfTime(ScheduledThreadPoolExecutor pool,
                                  Runnable r, int how) {
          switch (how) {
          case 0:
              pool.schedule(r, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
              break;
          case 1:
              pool.schedule(Executors.callable(r), Long.MAX_VALUE, TimeUnit.DAYS);
              break;
          case 2:
              pool.scheduleWithFixedDelay(r, Long.MAX_VALUE, 1000, TimeUnit.NANOSECONDS);
              break;
          case 3:
              pool.scheduleAtFixedRate(r, Long.MAX_VALUE, 1000, TimeUnit.MILLISECONDS);
              break;
          default:
              fail(String.valueOf(how));
          }
      }
  
      /**
       * Attempts to test exhaustively and deterministically, all 20
       * possible ways that one task can be scheduled in the maximal
       * distant future, while at the same time an existing tasks's time
       * has already expired.
       */
      void test(String[] args) throws Throwable {
          for (int nowHow = 0; nowHow < 4; nowHow++) {
              for (int thenHow = 0; thenHow < 4; thenHow++) {
  
                  final ScheduledThreadPoolExecutor pool
                      = new ScheduledThreadPoolExecutor(1);
                  final CountDownLatch runLatch     = new CountDownLatch(1);
                  final CountDownLatch busyLatch    = new CountDownLatch(1);
                  final CountDownLatch proceedLatch = new CountDownLatch(1);
                  final Runnable notifier = new Runnable() {
                          public void run() { runLatch.countDown(); }};
                  final Runnable neverRuns = new Runnable() {
                          public void run() { fail(); }};
                  final Runnable keepPoolBusy = new Runnable() {
                          public void run() {
                              try {
                                  busyLatch.countDown();
                                  proceedLatch.await();
                              } catch (Throwable t) { unexpected(t); }
                          }};
                  pool.schedule(keepPoolBusy, 0, TimeUnit.SECONDS);
                  busyLatch.await();
                  scheduleNow(pool, notifier, nowHow);
                  waitForNanoTimeTick();
                  scheduleAtTheEndOfTime(pool, neverRuns, thenHow);
                  proceedLatch.countDown();
  
                  check(runLatch.await(10L, TimeUnit.SECONDS));
                  equal(runLatch.getCount(), 0L);
  
                  pool.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
                  pool.shutdown();
              }
  
              final int nowHowCopy = nowHow;
              final ScheduledThreadPoolExecutor pool
                  = new ScheduledThreadPoolExecutor(1);
              final CountDownLatch runLatch = new CountDownLatch(1);
              final Runnable notifier = new Runnable() {
                      public void run() { runLatch.countDown(); }};
              final Runnable scheduleNowScheduler = new Runnable() {
                      public void run() {
                          try {
                              scheduleNow(pool, notifier, nowHowCopy);
                              waitForNanoTimeTick();
                          } catch (Throwable t) { unexpected(t); }
                      }};
              pool.scheduleWithFixedDelay(scheduleNowScheduler,
                                          0, Long.MAX_VALUE,
                                          TimeUnit.NANOSECONDS);
  
              check(runLatch.await(10L, TimeUnit.SECONDS));
              equal(runLatch.getCount(), 0L);
  
              pool.setExecuteExistingDelayedTasksAfterShutdownPolicy(false);
              pool.shutdown();
          }
      }
  
      //--------------------- Infrastructure ---------------------------
      volatile int passed = 0, failed = 0;
      void pass() {passed++;}
      void fail() {failed++; Thread.dumpStack();}
      void fail(String msg) {System.err.println(msg); fail();}
      void unexpected(Throwable t) {failed++; t.printStackTrace();}
      void check(boolean cond) {if (cond) pass(); else fail();}
      void equal(Object x, Object y) {
          if (x == null ? y == null : x.equals(y)) pass();
          else fail(x + " not equal to " + y);}
      public static void main(String[] args) throws Throwable {
          Class<?> k = new Object(){}.getClass().getEnclosingClass();
          try {k.getMethod("instanceMain",String[].class)
                  .invoke( k.newInstance(), (Object) args);}
          catch (Throwable e) {throw e.getCause();}}
      public void instanceMain(String[] args) throws Throwable {
          try {test(args);} catch (Throwable t) {unexpected(t);}
          System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
          if (failed > 0) throw new AssertionError("Some tests failed");}
  }
  