A method is described that comprises receiving from a classfile registration information. The registration information comprises a class name and a different method name for each of the class's methods. Each of the methods are modified with at least one additional byte code instruction to cause, for its respective method, a plug-in module's handler method to provide output function treatment for the respective method. Also, a plug-in pattern is referred to in order to determine which of a plurality of plug-in modules are appropriate for each of the class's methods. The plug-in pattern lists for each of the plug-in modules those of the methods that are to be handled with its corresponding output function treatment.