private void processAndWriteClass(Directory baseDir, File classfile) throws Exception {
   CtClass clazz = classPool.get(ClassNames.getClassName(baseDir, classfile));
   classInstrumenter.instrumentClass(clazz);
   if (clazz.isModified()) clazz.writeFile(processDirectory.getAbsolutePath());
   clazz.detach();
 }