Accessing an instance variable in main() method?

Question

 class Test {
     Test obj;
     public static void main(String[] args) {
         obj = new Test();
     }
 }

I am aware of the fact that instance variable and non-static methods are not accessible in a static method as static method don't know about anything on heap.

i want to ask if main is a static method how can i access an instance variable 'obj'.

Answer 1

Why accessing an instance variable in static main is impossible: Instance variable of which instance would you expect to access?

A possible misconception is that Java creates an instance of your main class when the application is started - that is not true. Java creates no such instance, you start in a static method, and it is up to you what instances of which classes you create.

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Ways out of this:

• Declare Test obj as static

  static Test obj;
  public static void main(String[] args) {
      obj = new Test();
  }
  

• Declare Test obj as local variable inside main

  public static void main(String[] args) {
      Test obj = new Test();
  }
  

• Create an instance of Test in your main, then you'll be able to access its instance variables

  static Test obj;
  public static void main(String[] args) {
      obj = new Test();
      obj.myInstanceVariable = ... // access of instance variable
  }