Answer Posted / ram

You need object of class 'X', but you want some custom
behavior for the object, not following the behavior defined
by the class 'X'.
Solution 1: create subclass 'Y' extending 'X'. Override
required methods(for custom behavior). create instance of Y
in your code and use it.
Solution 2: But you can achieve the above thing (need a
instance with different behavior) using anonymous inner
classes. The advantage here is, you don't even need to
create a subclass. Create an Anonymous inner class on the
fly, Just override the required behavior, and create an
instance and use it. Here is an example :

I have a class 'A'. By default, its getValue() method
returns whatever the value x holds. But i want to override
this behavior, it should return x+15.

public class AnonymousInnerClass {

public static void main(String[] args) {
A a = new A(10) {
@Override
public int getValue() {
return x + 15;
}
};
System.out.println(a.getValue());// 25 and not 10
}

}

class A {
int x;

public int getValue() {
return x;
}

A(int x) {
this.x = x;
}
}

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