BeginnersBook

  • Home
  • Java
    • Java OOPs
    • Java Collections
    • Java Examples
  • C
    • C Examples
  • C++
    • C++ Examples
  • DBMS
  • Computer Network
  • Python
    • Python Examples
  • More…
    • jQuery
    • Kotlin
    • WordPress
    • SEO
    • JSON
    • JSP
    • JSTL
    • Servlet
    • MongoDB
    • XML
    • Perl

Tag or marker interfaces in Java

Last Updated: September 11, 2022 by Chaitanya Singh | Filed Under: java

An empty interface is known as tag or marker interface. For example Serializable, EventListener, Remote(java.rmi.Remote) are tag interfaces, there are few other tag interfaces as well.

These interfaces do not have any field and methods in it. You must be thinking if they are empty why class implements them? What’s the use of it? Class implements them to claim the membership in a particular set. For example: If a class implements Serializable interface, it is claiming to be the member of Serializable classes, so if JVM (Java Virtual Machine) sees that a class is Serializable, it does some trick or special operation that helps in the serialization/de-serialization process.

Basically Tag interfaces are meaningful to the JVM (Java virtual machine). You can also create your own tag interfaces to segregate and categorize your code. It would improve the readability of your code.

This is how a tag interface looks:

package java.util;
public interface EventListener
{}
❮ PreviousNext ❯

Top Related Articles:

  1. C++ vs Java – Difference between C++ and Java
  2. Abstract Class in Java with example
  3. Introduction to Java programming
  4. Constructor Overloading in Java with examples
  5. Java Functional Interfaces

Tags: Java-OOPs

About the Author

I have 15 years of experience in the IT industry, working with renowned multinational corporations. Additionally, I have dedicated over a decade to teaching, allowing me to refine my skills in delivering information in a simple and easily understandable manner.

– Chaitanya

Comments

  1. neetu says

    January 28, 2017 at 9:20 AM

    only one public class can be in the single source file ?
    Public Class A
    {
    }
    Class B
    {
    }

    Whats class B ? public/private/protected?

    Reply
    • Mariano Aquino says

      March 13, 2017 at 6:43 PM

      with no keyword, visibility is default (package).

      Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Java Tutorial

Java Introduction

  • Java Index
  • Java Introduction
  • History of Java
  • Features of Java
  • C++ vs Java
  • JDK vs JRE vs JVM
  • JVM - Java Virtual Machine
  • First Java Program
  • Variables
  • Data Types
  • Operators

Java Flow Control

  • Java If-else
  • Java Switch-Case
  • Java For loop
  • Java while loop
  • Java do-while loop
  • Continue statement
  • break statement

Java Arrays

  • Java Arrays

OOPs Concepts

  • OOPs Concepts
  • Constructor
  • Java String
  • Static keyword
  • Inheritance
  • Types of inheritance
  • Aggregation
  • Association
  • Super Keyword
  • Method overloading
  • Method overriding
  • Overloading vs Overriding
  • Polymorphism
  • Types of polymorphism
  • Static and dynamic binding
  • Abstract class and methods
  • Interface
  • Abstract class vs interface
  • Encapsulation
  • Packages
  • Access modifiers
  • Garbage Collection
  • Inner classes
  • Static import
  • Static constructor

Java Exception Handling

  • Exception handling
  • Java try-catch
  • Java throw
  • Java throws
  • Checked and Unchecked Exceptions
  • Jav try catch finally
  • Exception Examples
  • Exception Propagation

Collections Framework

  • Collections in Java
  • Java ArrayList
  • Java LinkedList
  • Java Vector
  • Java HashSet
  • Java LinkedHashSet
  • Java TreeSet
  • Java HashMap
  • Java TreeMap
  • Java LinkedHashMap
  • Java Queue
  • Java PriorityQueue
  • Java Deque
  • Comparable interface
  • Comparator interface
  • Collections Interview Questions

MORE ...

  • Java Scanner Class
  • Java 8 Features
  • Java 9 Features
  • Java Conversion
  • Java Date
  • Java Multithreading
  • Java I/O
  • Java Serialization
  • Java Regex
  • Java AWT
  • Java Swing
  • Java Enum
  • Java Annotations
  • Java main method
  • Java Interview Q

Copyright © 2012 – 2025 BeginnersBook . Privacy Policy . Sitemap