Method overriding in Java

[Tharindu Priyath]

class A{
	int a=100;
	A(){
		printA();
	}
	void printA(){
		System.out.println("Class A : : "+a);
	}
}
class B extends A{
	int a=200;
	void printA(){
		System.out.println("Class B : "+a);
	}	
}
class Demo{
	public static void main(String args[]){
		new B();
	}
}

Output of this program is 0.Why?

[Campbell Ritchie]

You need to work out the order of invocation of the constructors. Write down which constructor is called and when. Then you can see what of the B object exists. The details are in the Java Language Specification. You will have to follow the links.

By the way: if this is an exam question (original or changed), you must tell us where it is from. It also shows the danger of calling methods not marked final or private from a constructor. It also shows the confusion which can occur when you have two fields of the same name. I hope you are posting this as an example of code you would never use in real life.

[Stevens Miller]

Yes, please do tell us where this nightmare came from. I had to step through it with the debugger three times before I understood why its output is what it is.