JAVA Class and Object Tutorial for Selenium WebDriver with Example

Class in Java

A class in java is declared using class keyword.

A class is a group of objects that has common properties. It is a template or blueprint from which objects are created.

When we create a class in java, the first step is to define keyword class and then name of the class.

Next is class body which starts with curly braces { } which enclose property and methods of the class in java.

Class is a user described blueprint or prototype from which objects are created.

It represents the set of properties or methods which might be common to all objects.

Class declaration include below additives, in order:

Modifiers : a class may be public or has default access.
class name : The name should begin with a initial letter.
body: The class in java body surrounded via braces { }.

Syntax of class:

// class Declaration
class class_name{ 

      data member; 

      method; 

}

// class Declaration

class class_name{

data member;

method;

}

Example: Simple Class Program [Area of Rectangle]

// create an class Student
class Student { 

  // field or data member or instance variable
  int id;
  String name;

  public static void main(String args[]) {

    // creating an object of Student
    Student s1 = new Student(); 

    // accessing member through reference variable
    System.out.println(s1.id);

    System.out.println(s1.name);

  }

}

// create an class Student

class Student {

// field or data member or instance variable

int id;

String name;

public static void main(String args[]) {

// creating an object of Student

Student s1 = new Student();

// accessing member through reference variable

System.out.println(s1.id);

System.out.println(s1.name);

}

Object in Java

In real–world, we see many objects round us like automobiles, dogs, cats and so on. these kinds of objects have a state and a behavior.

An object is an instance of a class.

If you compare the software object with a real-world object in java , they have very similar characteristics.

A class provides the blueprints for objects. So basically an object is created from a class. In Java the new keyword is used to create new object in java.

It’s miles a basic unit of object orientated Programming and represents the real existence entities.

An average Java program creates many objects, which as you already know, have interaction by way of invoking strategies.

An object includes :

state : it’s represented by attributes of an object. It additionally reflects the properties of an object.

behavior : it’s represented by means of methods of an object in java. It also reflects the reaction of an object with other objects.

identity : It gives a completely unique name to an object and allows one object to have interaction with different items.

Syntax to create new object:

// Create object of Dog class
Dog D1 = new Dog();

1 2	// Create object of Dog class Dog D1 = new Dog();

Example:

public class Dog {

  public static void main(String[] args) {

    // Object Creation method
    Dog D1 = new Dog(); 

  }

}

public class Dog {

public static void main(String[] args) {

// Object Creation method

Dog D1 = new Dog();

}