@Override
    public boolean containsKey(K key) {
        checkState(!destroyed, destroyedMessage);
        checkNotNull(key, ERROR_NULL_KEY);
        return get(key) != null;
    }
@Test
    public void testContainsKey() throws Exception {
        expectPeerMessage(clusterCommunicator);

        assertFalse(ecMap.containsKey(KEY1));
        ecMap.put(KEY1, VALUE1);
        assertTrue(ecMap.containsKey(KEY1));
        assertFalse(ecMap.containsKey(KEY2));
        ecMap.remove(KEY1);
        assertFalse(ecMap.containsKey(KEY1));
    }