Parameterized Types

A Generic class can have parameterized types where a type parameter can be substituted with a parameterized type. Following example will showcase above mentioned concept.

Example

Create the following java program using any editor of your choice.

GenericsTester.java

package com.tutorialspoint;

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


public class GenericsTester {
   public static void main(String[] args) {
  Box<Integer, List<String>> box
     = new Box<Integer, List<String>>();
  
  List<String> messages = new ArrayList<String>();
  
  messages.add("Hi");
  messages.add("Hello");
  messages.add("Bye");      
  
  box.add(Integer.valueOf(10),messages);
  System.out.printf("Integer Value :%d\n", box.getFirst());
  System.out.printf("String Value :%s\n", box.getSecond());
  
   }
}

class Box<T, S> {
   private T t;
   private S s;

   public void add(T t, S s) {
  this.t = t;
  this.s = s;
   }

   public T getFirst() {
  return t;
   } 

   public S getSecond() {
  return s;
   } 
}

This will produce the following result.

Output

Integer Value :10
String Value :[Hi, Hello, Bye]