What is the purpose of an instance variable in Java?

What is the purpose of an instance?

An instance variable reserves memory for the data your class needs. Let's assume you want to add a place for a string or int variable. You can use an instance variable to reserve that memory for the lifetime of the object. Each object will receive unique memory for its variables.

Where are instance variables used?

To use an instance variable an object of the class must be created. An instance variable is destroyed when the object it is associated with is destroyed. An instance variable does not compulsory need to be initialized. Instance variables are accessible inside the same class that declares them.

Why do you need to use instance variable in your program?

An instance variable is part of the blueprint for creating an object. It defines a datum that does not exist initially, but every time you create an object of that class's type (or subclass), that object will get its own (usually private) variable with that name inside of it. This is really the entire point behind OOP.

Why is it called a instance variable?

Instance variables are called so because they're instance(object) specific and are not shared among instances (objects)s, and changes done to variables of a particular instance will not reflect on others. When memory is allocated for an object in a heap, a slot for each of the instance variables is created.