System for modifying object oriented code

The system receives three sets of inputs: program class definitions, a set of rules, and additional class definitions to be merged with the program class definitions. There are three types of rules: the first rule is used to substitute the allocation of an object of a new class for the allocation of the object based on an original class; the second rule is used to change code that allocates an object of an original class to code that calls a static method that allocates the object of the original class; and the third rule is used to a replace a new static field for an original static field. The system separately reads each of the original class definitions into a class data structure and performs the modifications to the class data structure according to the set of rules. The resulting class data structure is written to an output stream.