Duplicate source code from GWT generator

Question

I want to duplicate the generate code for debugging purpose from a GWT generator

I wrote this code in order to do this but it is not working :

printWriter = new PrintWriter(
    new TeeOutputStream(
        new WriterOutputStream(context.tryCreate(logger, packageName, className)),  // Main writer
        new FileOutputStream(new File(System.getProperty("java.io.tmpdir") + File.separator + className + ".java"))     // Debug writer
    )
);

The error from GWT is Generator attempted to commit an unknown PrintWriter

Any other way to do this?