Book Image

Learning Selenium Testing Tools - Third Edition

Book Image

Learning Selenium Testing Tools - Third Edition

Overview of this book

Table of Contents (22 chapters)
Learning Selenium Testing Tools Third Edition
About the Author
About the Reviewers


All interface classes are by default Public and Abstract, and do not contain any completed methods.

Interface should implement (complete the body of a method) when all the abstract methods are inherited from the superclass (abstract class).

The actual use of interface will be structuring (setting or mandating to set off rules).

An example of a Java program with an interface

The following is an example of an interface in a Java program:

package MyFirstPackage;

interface sample_abs2 {
  void abstr_method ();
  void abstr_method1();

abstract  class sample_abs3 implements sample_abs2 {
  abstract void abstr_method2 ();

  void abstr_method2A(){
    System.out.println("Abstact class abstr_method2A");

class Interface extends sample_abs3 {//implements is a keyword used to complete the
//Interface Class
  public void abstr_method () {
    System.out.println("Interface abstr_method implementation");

  public void abstr_method1 () {
    System.out.println("Interface abstr_method1 implementation");

  public void abstr_method2 () {
    System.out.println("Abstact class abstr_method2 implementation");

  public static void main(String[] args) {
    System.out.println("interface class demo");
    Interface objI = new Interface();

The output will be as follows:

interface class demo
Interface abstr_method implementation
Interface abstr_method1 implementation
Abstact class abstr_method2 implementation
Abstact class abstr_method2A

Abstract classes compared with interfaces

For more details on abstract classes versus interfaces, visit

The this keyword

The this is a Java keyword that is used as an alternate for creating an instance for a nonstatic variable or method within a same class.

An example for the this keyword is as follows:

package MyFirstPackage;

class ThisKeyword{
  int id;  
  String name;

  //Constructor method
  ThisKeyword(int id, String name){
    //constructor variable and instance variable names are same = id; = name;

  void display(){
    System.out.println(id + " " + name);

  public static void main(String args[]){
    ThisKeyword objThis1 = new ThisKeyword(1234,"John");
    ThisKeyword objThis2 = new ThisKeyword(2456,"Smith");

The output for the preceding code will be as follows:

1234 John
2456 Smith