@Test
  public void lockOwnerThreadStackIsReported() throws InterruptedException {
    final Object syncObject = new Object();
    final Object releaseObject = new Object();
    final boolean[] blockingThreadWaiting = new boolean[1];
    final boolean[] blockedThreadWaiting = new boolean[1];
    Thread blockingThread = new Thread("blocking thread") {
      public void run() {
        synchronized (syncObject) {
          synchronized (releaseObject) {
            try {
              blockingThreadWaiting[0] = true;
              releaseObject.wait(timeoutInMilliseconds);
            } catch (InterruptedException e) {
              return;
            }
          }
        }
      }
    };
    Thread blockedThread = new Thread("blocked thread") {
      public void run() {
        blockedThreadWaiting[0] = true;
        synchronized (syncObject) {
        }
      }
    };
    blockingThread.start();
    await().until(() -> blockingThreadWaiting[0]);
    blockedThread.start();
    await().until(() -> blockedThreadWaiting[0]);
    try {
      AbstractExecutor executor = new AbstractExecutor("testGroup", blockedThread.getId()) {
        @Override
        public void handleExpiry(long stuckTime, Map<Long, ThreadInfo> map) {
          // no-op
        }
      };
      await().untilAsserted(() -> {
        Set<Long> threadIds = new HashSet<>();
        threadIds.add(blockedThread.getId());
        threadIds.add(blockingThread.getId());
        String threadReport = executor.createThreadReport(60000,
            ThreadsMonitoringProcess.createThreadInfoMap(threadIds, true, true));
        assertThat(threadReport)
            .contains(AbstractExecutor.LOCK_OWNER_THREAD_STACK + " for \"blocking thread\"");
        assertThat(threadReport).contains("Waiting on <" + syncObject + ">");
        assertThat(threadReport).contains("Owned By <blocking thread>");
        assertThat(threadReport).contains("- locked " + syncObject);
      });
    } finally {
      blockingThread.interrupt();
      blockedThread.interrupt();
      blockingThread.join(timeoutInMilliseconds);
      blockedThread.join(timeoutInMilliseconds);
    }
  }
If a thread is blocked by another thread we want to see the other thread's
stack in a "stuck thread" report. This test creates such a thread and
generates a "stuck thread" report to make sure the report on the other thread
is included.
geode-core/src/test/java/org/apache/geode/internal/monitoring/executor/AbstractExecutorGroupJUnitTest.java