ClassFileTransformer and how to transform the base class first

Question

Hello,
I've written a ClassFileTransformer that uses ASM to enhance classes at load time.
But some of the enhancements depends on possible enhancements to the super class.
Example: under some coditions a method doWork() is inserted. This method did not exist in any class (doWork is just an example, I use a name that is not accepted by the compiler but allowed by the JLS).
  public class A {}
  public class B extends A {}If the method doWork() was inserted into class A, then the doWork() of B has to call doWork() of class A:
   super.doWork().Currently I try to load the base class by using
   loader.loadClass(superName.replace('/', '.'));this loads the super class but without passing my transformer !
How can I solve this ?

Answer 1

Looking at the comments in ClassFileTransformer.java and the code in ClassLoader, it seems the transformers are called only for class files that get a ClassFormatError. Transformers are intended to fix old broken/incompatible class files on the fly.
I guess the intended way to do what you are doing is to define a custom class loader. Read class into byte[], transform, call defineClass() on the transformed byte[]. Google for java custom class loader for examples.