understanding class

[mitra]

Hi everybody........
Please make me understand of the following program line by line, basically from line 8.

class Program21_21 {
public void m(){
System.out.println("m method in Program21_21 class");
}
}


public class Program21{
public Program21_21 m(){
return new Program21_21(){
public void m(){
System.out.println("m method in Program21 class");
}
};
}

public static void main(String args[]){
Program21_21 obj = new Program21().m();
obj.m();
}
}


output is -- m method in Program21 class

this program is not clear to me.
Thanks.........

[DarrylBurke]

Who wrote the code?

db

[mitra]

output is -- m method in Program21 class

[Norm]

Which method prints that message?

[mitra]

Which method prints that message?

from method m() of class Program21


In this program there are two class --
1. Program21_21

2. Program21

[Norm]

What class does the obj variable refer to? Which method will be called in main?

[mitra]

What class does the obj variable refer to? Which method will be called in main?

I'm totally confuse about these code.

[Norm]

Here's a rewrite that should do the same thing:

// output is -- m method in Program21 class


public class TestInheritance {

  static class Program21_21 {
    public void m(){
      System.out.println("m method in Program21_21 class");
    }
  }
  
  
  static class Program21{
  
    // a method
    public Program21_21 method(){
      // Create new object and return it
      return new Program21_21(){
        @Override 
        public void m(){
          System.out.println("m method in Program21 class");
        }
      };
    }
  } // end class
  
  public static void main(String args[]) {
    Program21 pgm21 = new Program21();  // create an instance
    Program21_21 obj = pgm21.method();  // call a method to get another object
    obj.m();                                           // call a method on new object
  } // end main
  
} // end class Test....

[mitra]

Here's a rewrite that should do the same thing:

// output is -- m method in Program21 class


public class TestInheritance {

  static class Program21_21 {
    public void m(){
      System.out.println("m method in Program21_21 class");
    }
  }
  
  
  static class Program21{
  
    // a method
    public Program21_21 method(){
      // Create new object and return it
      return new Program21_21(){
        @Override 
        public void m(){
          System.out.println("m method in Program21 class");
        }
      };
    }
  } // end class
  
  public static void main(String args[]) {
    Program21 pgm21 = new Program21();  // create an instance
    Program21_21 obj = pgm21.method();  // call a method to get another object
    obj.m();                                           // call a method on new object
  } // end main
  
} // end class Test....

Thanks for ur help.
But could u explain me actually what happen in these code ---


static class Program21{

// a method
public Program21_21 method(){
// Create new object and return it
return new Program21_21(){
@Override
public void m(){
System.out.println("m method in Program21 class");
}
};
}
} // end class

[Norm]

There is a class, the class has a method, the method returns a reference to another class.

[mitra]

Thanks Norm........