package com.tutorialspoint;

import java.util.ArrayList;
import java.util.List;

public class GenericsTester {

   public static void addCat(List super Cat> catList) {
      catList.add(new RedCat());
      System.out.println("Cat Added");
   }

   public static void main(String[] args) {
      List animalList= new ArrayList();
      List catList= new ArrayList();
      List redCatList= new ArrayList();
      List dogList= new ArrayList();

      //add list of super class Animal of Cat class
      addCat(animalList);

      //add list of Cat class
      addCat(catList);

      //compile time error
      //can not add list of subclass RedCat of Cat class
      //addCat(redCatList);

      //compile time error
      //can not add list of subclass Dog of Superclass Animal of Cat class
      //addCat.addMethod(dogList); 
   }
}
class Animal {}

class Cat extends Animal {}

class RedCat extends Cat {}

class Dog extends Animal {}

Cat Added
Cat Added