public Object invokeMethod(String className, String methodName,
   Object[] args) throws Exception{

  Class ownerClass = Class.forName(className); 
  Object owner = ownerClass.newInstance();
    
    Class[] argsClass = new Class[args.length];  
  
    for (int i = 0, j = args.length; i < j; i++) {  
     
      argsClass[i] = args[i].getClass();        
    }  
  
    Method method = ownerClass.getMethod(methodName, argsClass);  
  return method.invoke(owner, args);
 }

for (int i = 0, j = args.length; i < j; i++) {  
     
      argsClass[i] = args[i].getClass();       
    }  

for (int i = 0, j = args.length; i < j; i++) {  
     if(i == 3){
      argsClass[i] = HttpServletResponse.class;  
     }
     else{
      argsClass[i] = args[i].getClass();  
     }
      
    }