public void clear() {
        for (int i = 0; i < sections.length; i++) {
            sections[i].clear();
        }
    }
@Test
    public void testClear() {
        ConcurrentOpenHashMap<String, String> map = ConcurrentOpenHashMap.<String, String>newBuilder()
                .expectedItems(2)
                .concurrencyLevel(1)
                .autoShrink(true)
                .mapIdleFactor(0.25f)
                .build();
        assertTrue(map.capacity() == 4);

        assertNull(map.put("k1", "v1"));
        assertNull(map.put("k2", "v2"));
        assertNull(map.put("k3", "v3"));

        assertTrue(map.capacity() == 8);
        map.clear();
        assertTrue(map.capacity() == 4);
    }