A classfile modification method is described. The classfile modification method entails converting a classfile into a collection of objects whose organization is derived from the classfile's organization. The collection of objects comprise unique objects for each method information structure found in the classfile. Each of the unique objects reference other objects in the organization. The other objects represent their corresponding unique object's method information structure's byte code instructions. The classfile modification method also entails adding at least one additional other object to an arrangement of other objects that are referenced to a unique object. The at least one additional other object corresponds to at least one byte code instruction that causes a plug-in module's handler method to provide output function treatment for the unique object's method. The classfile modification method also entails converting the resulting collection of objects into a modified version of the classfile.