public void uncaughtException(Thread t, Throwable e) {
              exceptions.add(e);
            }
          });
      threads.add(thread);
    }
    for (Thread t : threads) {
      t.start();
    }
    for (Thread t : threads) {
      Uninterruptibles.joinUninterruptibly(t);
    }
    return exceptions;
  }

  private static int getNonGoldenRandomKey() {
    int key;
    do {