Understanding method declarations created with Object ob = new Object(){ ... };

[Ehsan Rahman]

Hi All,

This is probably an easy one ...

  
public class TestThreadMethod {
    int i;

    public void aMethod(){}

    public static void main(String argsp[])
    {
        TestThreadMethod ob = new TestThreadMethod(){
            @Override
            public void aMethod(){ System.out.println("What is all this?");
            }
        };

       ob.aMethod();
    }
}  

Why is it that if line 5 is commented out then the method in 11 is not applicable (and results in a compiler error), even though it does override as the code is above.

I've noticed this type of over-ride used a lot with the run() method when creating Threads.

Many Thanks,
Ehsan

[John de Michele]

The @Override annotation lets the compiler know that you're overriding or implementing a method in a superclass. By commenting out the original method, you're no longer overriding it in your anonymous subclass.

John.

[Ehsan Rahman]

Thanks. Yes, it is an anonymous class.

http://docstore.mik.ua/orelly/java-ent/jnut/ch03_12.htm
Syntax: new class-name ( [ argument-list ] ) { class-body }

http://www.coderanch.com/t/409946/Java-General-beginner/java/call-method-anonymous-class

   (new Object() {   
  void foo() {   
    System.out.println("foo");   
   }   
}).foo();