modify method in byte code using ASM.

[jing hu]

For the class Test

public class Test{
    public void f(){
        int i = 10;
   }
    public void g(){
        int i = 10;
   }
}

Now I have the Test.class and have no source code.
I want to modify method f() like below.
add " int j = 10;" before " inti = 10;"

    public void f(){
        int j = 10;
        int i = 10;
   }

using ASM how to implement this.
Thank you very much.

[Ashok Suthar]

Hi,

Extend the test Class and override its methods which you want to modify... If that fulfils your purpose.

I am not sure what you are trying to do here.

[jing hu]

I don't want to recompile this .class. recompiling the class may be hard work.
int my thread , the Test is just only a sample.
So I want to do some modification in the .class file. That is my main purpose.

[Campbell Ritchie]

ASM? That's hardly a beginner's topic. I shall try moving this to "advanced."