Java Generics - Classes


Advertisements

A generic class declaration looks like a non-generic class declaration, except that the class name is followed by a type parameter section.

The type parameter section of a generic class can have one or more type parameters separated by commas. These classes are known as parameterized classes or parameterized types because they accept one or more parameters.

Syntax

public class Box<T> {
   private T t;
}

Where

  • Box − Box is a generic class.

  • T − The generic type parameter passed to generic class. It can take any Object.

  • t − Instance of generic type T.

Description

The T is a type parameter passed to the generic class Box and should be passed when a Box object is created.

Example

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

GenericsTester.java

package com.tutorialspoint;

public class GenericsTester {
   public static void main(String[] args) {
      Box<Integer> integerBox = new Box<Integer>();
      Box<String> stringBox = new Box<String>();

      integerBox.add(new Integer(10));
      stringBox.add(new String("Hello World"));

      System.out.printf("Integer Value :%d\n", integerBox.get());
      System.out.printf("String Value :%s\n", stringBox.get());
   }
}

class Box<T> {
   private T t;

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

   public T get() {
      return t;
   }   
}

This will produce the following result.

Output

Integer Value :10
String Value :Hello World

Useful Video Courses


Video

Java Date and Time Online Training

16 Lectures 2 hours

Malhar Lathkar

Video

Java Servlet Online Training

19 Lectures 5 hours

Malhar Lathkar

Video

JavaScript Online Training

25 Lectures 2.5 hours

Anadi Sharma

Video

Java Online Training

Most Popular

126 Lectures 7 hours

Tushar Kale

Video

Java Essential Training

119 Lectures 17.5 hours

Monica Mittal

Video

Java Essentials Online Training

76 Lectures 7 hours

Arnab Chakraborty

Advertisements