public int incrementAndGet() {
        Integer index = this.threadLocalIndex.get();
        if (null == index) {
            index = random.nextInt();
        }
        this.threadLocalIndex.set(++index);
        return index & POSITIVE_MASK;
    }
@Test
    public void testIncrementAndGet2() throws Exception {
        ThreadLocalIndex localIndex = new ThreadLocalIndex();
        int initialVal = localIndex.incrementAndGet();
        assertThat(initialVal >= 0).isTrue();
    }