Object and Class in java

In this post, we will learn about Object and class in java. As Java is an object-oriented programming language, we need to design our program using Objects and classes.

Object: An entity that has state and behavior may be termed as Object.
For example: Employee has state with name, age and department, and behavior such as working on the assignment.

Class: A class is a blueprint/template that defines state and behavior of objects.
For example: Employee is a class in above example.

Object is an instance of class: As object are created on the basis of blueprint/template that class provides, Object is an instance of the class.

Let’s create a simple class:

Below diagram will explain the structure of class:

Let’ s see an example of Object now:

You can create object of above class as below:

Objects are stored in heap memory.
When above statement gets called, physical object is created in the memory as below:

Now let’s create two objects i.e. employee1 and employe2 and set name and age for these two objects.

These two objects will be created in memory as below:

Object are created using constructor with the help of new operator. We will see more about in subsequent tutorials.

that’s all about Object and class in java.