public ForkJoinPool getDefaultForkJoinPool() {
    if (defaultForkJoinPool == null){
      logThreadPoolCreation(DEFAULT_FORK_JOIN_POOL_NAME, configuration.getDefaultForkJoinPoolSize());
      defaultForkJoinPool = new ForkJoinPool(
        configuration.getDefaultForkJoinPoolSize(),
        createNamedFactory(DEFAULT_FORK_JOIN_POOL_NAME),
        (t, e) -> {
          LOG.error("Unexpected exception in thread: " + t, e);
          throw new RuntimeException(e);
        },
        false
      );
    }
    return defaultForkJoinPool;
  }
Determines the need of waiting for all tasks to be processed:
true - next task would be processed
false - next task would be cancelled
@param <T>
ambari-server/src/main/java/org/apache/ambari/server/utils/ThreadPools.java