Execute main method inside inner class [duplicate]

Question

How to execut main method, if it is present in static inner class?
Main method is present in static inner class and we need to execute that main method.

class A {
     static class B {
          public static void main(String[] args) {
             System.out.println("Done");
          }
     }
}

Answer 1

Try something like this:

  java A$B

Update according to comments:

In linux shell you should escape $. So the command became:

java 'A$B'

Answer 2

Its just like simple class. Run command java A$B When inner class is compiled, it is prepended with outer class name In this case you two class files. i.e . A.class and A$B.class

• java command takes the classname as the argument and not the filename
• So simple command java A$B will do the work
• If you have anonymous classes then the classnames will be like OuterClass$1, OuterClass$1 and so on.

So if you modify your example as follows, now including anonymous and method local inner classes

import java.io.Serializable;

public class A {
    static class B {
        public static void main(String[] args) {
            System.out.println("Done");
            Serializable obj = new Serializable() {
            };
            Serializable obj1 = new Serializable() {
            };
            class MethodLocalClass {
            }                                           
        }
    }
}

Then the class files you will get are A.class, A$B.class, A$B$1.class, A$B$2.class for the anonymous classes and A$B$1MethodLocalClass.class.

Hope this example helps a bit :)