So two things that are happening here:
1) clazz.getClassFile().setAccessFlags(clazz.getModifiers() & ~Modifier.FINAL) is invalid since the modifiers have different info/flags than the accessFlag and then this trips java/javassist.
For instance for a final enum class inside a static inner class:
0x4019 ctClass.getModifiers()
ENUM, FINAL, STATIC, PUBLIC
0x4009 ctClass.getModifiers() & ~Modifiers.FINAL
ENUM, FINAL, STATIC, PUBLIC
0x4031 ctClass.getClassFile().getAccessFlags()
ENUM, FINAL, SYNCHRONIZED, PUBLIC
0x4021 ctClass.getClassFile().getAccessFlags() & ~Modifiers.FINAL
ENUM, SYNCHRONIZED, PUBLIC
0x4021 ctClass.getClassFile().getAccessFlags() & ~AccessFlags.FINAL
ENUM, SYNCHRONIZED, PUBLIC
This leaves us with 2).
2) We can't use clazz.setModifiers(clazz.getModifiers() & ~Modifiers.FINAL) because it will try to update the inner classes of the class and this might trigger an exception if an inner CtClass was already loaded and frozen.
The reason it tries to update the inner classes is because it detects that the STATIC flag might have changed and this needs to be propagated to all inner classes, even if no change was needed!
So two things that are happening here: 1)
clazz.getClassFile().setAccessFlags(clazz.getModifiers() & ~Modifier.FINAL)is invalid since the modifiers have different info/flags than theaccessFlagand then this trips java/javassist.For instance for a final enum class inside a static inner class:
This leaves us with 2).
2) We can't use
clazz.setModifiers(clazz.getModifiers() & ~Modifiers.FINAL)because it will try to update the inner classes of the class and this might trigger an exception if an inner CtClass was already loaded and frozen.The reason it tries to update the inner classes is because it detects that the STATIC flag might have changed and this needs to be propagated to all inner classes, even if no change was needed!