Object

It is a basic runtime entity that has a state & behaviour & identity.
It is an instance(result) of a class.
It is made up of attributes and methods

Syntax :

class_name object_name= new class_name();

Example:

 B obj= new B();         //here obj is attribute
 obj.s();                //here s() is method

Characteristics of the objects:

State: It represents the value of an object.
Behaviour: It represents the functionality of an object.
Identity: Gives uniqueness to the object i.e. student ID card etc.

Example of the three characteristics of an Object:

In the real world, we can consider a Car as an object.

STATE BEHAVIOUR IDENTITY
Speed Gear vehicle

Class

Blueprint from which object is created.

JAVA class contains:

Fields.
Methods.
Constructor.
Blocks.

Syntax:

access_modifier class class_name
  {
      // var
      // method
      // constructor
      // blocks and statement. 
  }

Example: Creation of class

Access
modifier keyword class_name
   |       |        |
public   class   HelloWorld {
	public static void main(String[] args) {
		System.out.println("hello");
	}
}

Output:

hello

Example: for calling and accessing the class

package quipohouse;
public class HelloWorld {
	int a = 10;

	public static void main(String[] args) {

		HelloWorld obj = new HelloWorld();   // here helloWorld is a class and obj is an object
		System.out.println(obj.a);           // calling instance variable by its object
	}
}

Output: