GsonMerger.java

	@SuppressWarnings("unchecked")
	public static <T extends JsonElement> T merge(final T obj1, final T obj2)
	{
		if(obj1 == null)
			return clone(obj2);
		if(obj2 == null)
			return clone(obj1);
		if(obj1 instanceof JsonObject)
		{
			final Map<String, JsonElement> merged = new HashMap<>();
			obj2.getAsJsonObject().entrySet().forEach(entry -> merged.put(entry.getKey(), entry.getValue()));
			obj1.getAsJsonObject().entrySet().forEach(entry -> merged.put(entry.getKey(), merge(entry.getValue(), obj2.getAsJsonObject().get(entry.getKey()))));
			final JsonObject mergedJson = new JsonObject();
			merged.forEach((key, value) -> mergedJson.add(key, value));
			return (T) mergedJson;
		}
		if(obj1 instanceof JsonArray)
		{
			final List<JsonElement> merged = new ArrayList<>();
			obj1.getAsJsonArray().forEach(element -> merged.add(element));
			obj2.getAsJsonArray().forEach(element -> {
				if(!merged.contains(element))
					merged.add(element);
			});
			final JsonArray mergedJson = new JsonArray();
			merged.forEach(mergedJson::add);
			return (T) mergedJson;
		}
		if(obj1 instanceof JsonPrimitive)
			return obj1;
		throw new UnsupportedOperationException("Cannot merge " + obj1.getClass().getName());
	}

	@SuppressWarnings("unchecked")
	public static <T extends JsonElement> T clone(final T json)
	{
		if(json instanceof JsonObject)
		{
			final JsonObject copyOf = (JsonObject) json;
			final JsonObject clone = new JsonObject();
			copyOf.entrySet().forEach(entry -> clone.add(entry.getKey(), clone(entry.getValue())));
			return (T) clone;
		}
		if(json instanceof JsonArray)
		{
			final JsonArray copyOf = (JsonArray) json;
			final JsonArray clone = new JsonArray();
			copyOf.forEach(element -> clone.add(clone(element)));
			return (T) clone;
		}
		if(json instanceof JsonPrimitive)
		{
			return json;
		}
		throw new UnsupportedOperationException("Cannot clone " + json.getClass().getName());
	}