What is the exact meaning of instantiate in JAVA

First of all Declaring mean:

Simple meaning of instantiate is creating an object from class.

ClassName obj = new ClassName();

What is a object?

  • An instance of a class. From one class we can create many instances.
  • They are the basic runtime entities in in our program.
  • They may also represent user-defined data types such as lists and vectors.
  • Any programming problem is analyzed in terms of objects and nature of communication between them.

As a example:

//Define a reference(a variable) which can hold a `Person` obect.
Person p;
//Create a Person object(instantiate).
//new - use to allocate memory space for the new object
p = new Person();

What is a nested class?

A class that defined inside a class is called nested class. There 2 categories of nested classes.

  1. inner classes
  2. local classes
  3. annonymous classes

Inner class:

  • Inner class can only be accessed by the outer class. Not by any other class.
  • Inner class is a member of outer class.
  • Outer class can access inner class without importing.
  • Inner class can access any attribute or a method belong to outer directly.
  • Outer class cannot access directly to a inner class.

Example for a inner class:

class Outer{
   int i = 10;
   void main(){
      //instantiate inner class.
      Inner in = new Inner();

   class Inner{
      void show(){

What is a local class?

Which are classes that are defined in a block.


public class{
  int i = 10;

  public main(){
     class A{
        void show(){

     //inside the method instantiate local class.
     A obj = new obj();
  //outside the main() -block(method)
  //inside another method instantiate local class.
  public test(){
    A obj = new A();

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