Thread: Override class method

Hello

I have a external jar library that has many classes and methods. My question is, how can I rewrite a existing method without changing the library?

Ex:

(External jar)
Class Original{
public int doit(a){
return a+1;
}
}


So normally using
Original object = new Original();
System.out.print(object(2));

The output is 3.


Now i want to alter the method to
public int doit(a){
return a+2;
}


I want the output be 4.

Now, i cannot alter the Original class or any the coded used for object creation so creating an extension of class Original is not viable.

Any thoughts?

Main.java

public class Main {
	public static void main(String[] args) throws Exception {
		Original object = new Original();
		System.out.print(object.doit());
	}
}

Original.java

public class Original {
	public int doit(){
		return 2;
	}
}

Mutated.java

public class Mutated extends Original{
	@Override public int doit(){
		return 3;
	}
}

Output: 2
Output expected: 3

So, any advices on this? I can only change Mutated.java

Please do not double post your question. Your other post has been deleted.

In the main, create the Mutated class, not the original class to expect an output of 3.

I'm just allowed to change Mutated.java . Is there a way to do it?

Originally Posted by mekie

I'm just allowed to change Mutated.java . Is there a way to do it?

You did change it, at least relative to Original.