public <K, V> V getOrDefault(String map, K key, V defaultValue) {
		V value = get(map, key);
		return value == null ? defaultValue : value;
	}
For support data clustering using hazelcast instance.

@since 3.5.0
ngrinder-controller/src/main/java/org/ngrinder/infra/hazelcast/HazelcastService.java