A system and method for automatic invocation of object initializers, or constructors, for superclasses featuring the ability to modify the contents of classes of existing applications at runtime, which includes adding new superclasses to the class inheritance hierarchy of the existing classes. The system redefines the content of classes of the existing classes and the new superclasses during the loading of the classes to additionally include code statements that invoke constructors of the redefined classes and the new superclasses. The invocation of the constructors at runtime performs the initialization of the objects.