public void start() {
    Preconditions.checkState(monitorThread == null,
      "JvmPauseMonitor thread is Already started");
    monitorThread = new Daemon(new Monitor());
    monitorThread.start();
  }
log INFO if we detect a pause longer than this threshold
common/src/java/org/apache/hadoop/hive/common/JvmPauseMonitor.java