possible below code.
e.g)
@Override
	protected String createJsonStringEntity(Object data) {

		String createJsonStringEntity = super.createJsonStringEntity(data);

		JsonElement el = new JsonParser().parse(createJsonStringEntity);
		log.info("request body to json - " + System.getProperty("line.separator") + new GsonBuilder().setPrettyPrinting().create().toJson(el));

		return createJsonStringEntity;
	}
}