How will it execute?

[Shailesh Phatak]

How do i execute this type of inner class?

 interface Interf{
   public void drink();
   }

class Water{
          void drinkWater(Interf IF)
           {
             System.out.println("This is water class");
           }
      }
      
class InnerAnoInterfaceClass {

   public void go(){

// How do i call this so that the ans would be  "Human drinks water in main class"
    
        Water w=new Water();
        d.drinkWater(new Interf() {
           public void drink(){
               System.out.println("Human drinks water in main class ");
            }
      });
   }
 }  

   public static void main(String args[]){
         //     ?
           //      ?
             //        ?      


       }
  }   

How do i call this so that the ans would be "Human drinks water in main class"

[Harpreet Singh janda]

There are a few syntex errors in your code. Can you please refine and post it again?

[Shailesh Phatak]

I cant.. I tried a lot to execute it anyhow. But i am sure that there is no syntax error in go() part of InnerAnoInterface Class

[Minhaj Mehmood]

Try this...

interface Interf{
	public void drink();
}

class Water{
	void drinkWater(Interf IF){
		IF.drink();
		System.exit(0);
		System.out.println("This is water class");
	}
}

public class InnerAnoInterfaceClass {

	public void go(){

		// How do i call this so that the ans would be  "Human drinks water in main class"

		Water w=new Water();

		w.drinkWater(new Interf() {
			public void drink(){
				System.out.println("Human drinks water in main class ");
			}
		});

	}


	public static void main(String args[]){
		new InnerAnoInterfaceClass().go();
	}
}

[Shailesh Phatak]

Thanks MM for your help.. But what kind of magic going on here ?

[Jim Hoglund]

There are several things to look at. First, on line 06 below, go() is called
on the anonymous class created by new. Okay so far?

class InnerAnoInterfaceClass {
   public void go() {
      // How do i call this so that the ans would be "Human drinks water in main class"
   }
   public static void main(String args[]) {
      new InnerAnoInterfaceClass().go();
   }
}

Then looking at the definition of Water, its drinkWater() method immediately calls
drink() on an Interf object that is passed in. The key to the puzzle is to figure out
how this Interf object is created.

Notice below that the parameter passed to drinkWater() continues all the way from
the 'new' on line 02 through line 06. The drinkWater() call ends with ); on line 06.

      Water w = new Water();
      w.drinkWater(new Interf() {
         public void drink() {
            System.out.println("Human drinks water in main class ");
         }
      });

Below again is the type Interf parameter from above. Line 07 starts a rewritten version
that illustrates what is happening.

new Interf() {
   public void drink() {
      System.out.println("Human drinks water in main class ");
   }
}

class [ANONYMOUS] implements Interf {
   public void drink() {
      System.out.println("Human drinks water in main class ");
   }
}

So you can 'new' an interface, creating an anonymous class, if you implement the interface's
methods in this way. Right in the call parameter list, Interf is implemented by a 'no-name'
class and then the 'no-name' class is instantiated as a type Interf object. Pretty cool, ey?

Jim... ...

[Shailesh Phatak]

Thanks Jim for the elaborative reply
I used the correct word i think in the last post i.e "MAGIC"