Not able to compile custom jar

Hello Experts

I have a requirement where I need  to modify a custom jar (already  existing) , change some codes and redeploy back in ESO server .  The process we followed is -

1) downloaded ESOSERVER.EAR file from server and  extracted the jar files

2) imported the files throw java editor as a project

3) changed the java codes in custom java file 

However , while compiling  and making .class file in editor, I can see that the relevant changes are not reflected in the file . For testing this - we again de-compile the class file to a java file and can not see the changes .

Can someone throw some light -what we are missing here ?

Thanks

Sudipta