public static HazelcastInstance getOrCreateHazelcastInstance() {
        return HazelcastInstanceFactory.getOrCreateHazelcastInstance(null);
    }
@Test
    public void getOrCreateDefaultHazelcastInstance() {
        String hzConfigProperty = System.getProperty(HAZELCAST_CONFIG);
        try {
            System.setProperty(HAZELCAST_CONFIG, "classpath:test-hazelcast-jcache.xml");
            HazelcastInstance hz1 = Hazelcast.getOrCreateHazelcastInstance();
            HazelcastInstance hz2 = Hazelcast.getOrCreateHazelcastInstance();
            assertEquals("Calling two times getOrCreateHazelcastInstance should return same instance", hz1,
                    hz2);
        } finally {
            if (hzConfigProperty == null) {
                System.clearProperty(HAZELCAST_CONFIG);
            } else {
                System.setProperty(HAZELCAST_CONFIG, hzConfigProperty);
            }
        }
    }