code: public static Method checkMethodExist(Class<?> clazz, String uniqueMethodName) {
  		if (clazz == null || StrUtils.isEmpty(uniqueMethodName))
  			return null;
  		Map<String, Object> methodMap = uniqueMethodCache.get(clazz);
  		if (methodMap != null && !methodMap.isEmpty()) {
  			Object result = methodMap.get(uniqueMethodName);
  			if (result != null) {
  				if (ClassOrMethodNotExist.class.equals(result))
  					return null;
  				else
  					return (Method) result;
  			}
  		}
  		if (methodMap == null) {
  			methodMap = new HashMap<String, Object>();
  			uniqueMethodCache.put(clazz, methodMap);
  		}
  		Method[] methods = clazz.getMethods();
  		for (Method method : methods)
  			if (uniqueMethodName != null && uniqueMethodName.equals(method.getName())) {
  				methodMap.put(uniqueMethodName, method);
  				return method;
  			}
  		methodMap.put(uniqueMethodName, ClassOrMethodNotExist.class);
  		return null;
  	}
docs: Check if a unique method name exists in class, if exist return the method,
  otherwise return null