Hello!

I've written a tool that removes the final modifier from class files. That works perfectly with "outer" classes, but with inner classes javassist seems to fail. Here is a small test case.

The class FinalRemover does the job:

package test;

import javassist.ClassPool;
import javassist.CtClass;
import javassist.Modifier;

public class FinalRemover {

 public static void main(String[] args) throws Exception {
 process("test.NoInner");
 process("test.WithInner");
 process("test.WithInner$NotStatic");
 process("test.WithInner$Static");
 }

 public static void process(String className) throws Exception {
 System.out.println("Processing class: " + className);
 ClassPool pool = ClassPool.getDefault();

 CtClass cc = pool.get(className);
 removeFinal(cc);

 if (Modifier.isFinal(cc.getModifiers())) {
 throw new IllegalStateException("Class '" + className + "' is not final?!?");
 }

 cc.writeFile("/tmp/test_patched/patched");
 System.out.println("Class was written: " + className);
 System.out.println();
 }

 protected static void removeFinal(CtClass clazz) {

 int modifiers = clazz.getModifiers();

 if (Modifier.isFinal(modifiers)) {
 System.out.println("Removing final modifier: " + clazz.getName());
 int notFinalModifier = Modifier.clear(modifiers, Modifier.FINAL);
 clazz.setModifiers(notFinalModifier);
 }

 }

}

The class NoInner has no inner class:

package test;

public final class NoInner {

}

Finally, the class WithInner has two inner classes:

package test;

public class WithInner {

 public WithInner() {
 super();
 }

 public static final class Static {

 public static final String CONST = "Static inner class";

 }

 public final class NotStatic {

 public static final String CONST = "Not static inner class";

 }

}

Running the tool writes the following output:

Processing class: test.NoInner
Removing final modifier: test.NoInner
Class was written: test.NoInner

Processing class: test.WithInner
Class was written: test.WithInner

Processing class: test.WithInner$NotStatic
Removing final modifier: test.WithInner$NotStatic
Class was written: test.WithInner$NotStatic

Processing class: test.WithInner$Static
Removing final modifier: test.WithInner$Static
Class was written: test.WithInner$Static

I decompiled the written class files using JAD. A diff between the original and the patched class NoInner shows the expected result:

$ diff orig/NoInner.jad patched/NoInner.jad
9c9
< public final class NoInner
---
> public class NoInner

But, between the original and the patched class WithInner, there is no difference:

$ diff orig/WithInner.jad patched/WithInner.jad

Thus, the final modifier was not removed from the byte code. Please note the IllegalStateException in my code: javassist thinks that modifier was removed, but it is still contained in the byte code written the the file.

Any ideas?

Regards

Martin