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Thread: Override class method

  1. #1
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    Default 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?


  2. #2
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    Default Re: Override class method

    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

  3. #3
    Administrator copeg's Avatar
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    Default Re: Override class method

    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.

  4. #4
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    Default Re: Override class method

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

  5. #5
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    Default Re: Override class method

    Quote Originally Posted by mekie View Post
    I'm just allowed to change Mutated.java . Is there a way to do it?
    You did change it, at least relative to Original.

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