@Test
public void shouldObtain10MillionCountersFromThreadSafeUsingMultipleThreads() {

    print(counter.nextKey());
    for (int j = 0; j != 100; ++j) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i != 100000; ++i) {
                    counter.nextKey();
                }
            }
        }).run();
    }
    print(counter.nextKey());
}