ASM-based class transformation affect class loading?

Hi all:

I met a strange problem when using ASM to transform my client code at load
time (excluding all JDK code already).

It seems that my transformer is highly likely to affect the class loading
process. Please refer to the simple code below
for illustration:

Here is my simple ClassFileTransformer for load time class transformation,
all transformation operations are
in the treeAPITransform(byte[]) method. It is actually a fairly simple *
intra-method* transformation based on the "*tree api" *
of ASM (just adding tracing method at the begin/end of each method call)


@Override
    public byte[] transform(ClassLoader loader, String className,  Class<?>
clazz, ProtectionDomain domain,   byte[] bytes) {
         //code omitted here, for excluding all JDK classes

           /*I print each loaded class for debugging */
(1)   System.err.println("---- load class: " + className);

        try {
(2)          return this.treeAPITransform(bytes);   //my simple
transformation implementation
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

The weird thing is that statement (1) does not print out some obviously
loaded classes (which has definitely been initialized and executed).

If I remove statement (2), or change that to "return null", every thing OK.
all classes loaded are printed out at statement (1).

I feel very confused on this point. I am wondering will ASM-based
intra-method transformation affect the class loading? or
did I instrument some extra classes by accident? or I should not use the
tree api? or there is any tricks on this point?

P.S. I use the ClassCheckerAdapter in ASM to check the validity of
transformed bytecode after transformation. and no error messages
are issued.

thanks. Any comments are highly appreciated!!!

-Sai

-- 
You receive this message as a subscriber of the [email protected] mailing list.
To unsubscribe: mailto:[email protected]
For general help: mailto:[email protected]?subject=help
OW2 mailing lists service home page: http://www.ow2.org/wws