| Java has multiple inheritance of interfaces, but only single inheritance of code. This situation leads to code being duplicated in Java library classes and applications. We describe a generalization of a Java Virtual Machine (JVM) to support multiple inheritance of code.; Our approach places code in interfaces, without requiring language syntax changes or compiler modifications. In our extended JVM, we use interfaces to represent either new types of interfaces with code or traditional interfaces in Java. We define and implement a super call mechanism resembling the one in C++, in which the programmer can specify an inheritance path to the desired superinterface implementation. We introduce a simple notation for super calls to interfaces. Furthermore, we develop scripts that allow a programmer to use multiple code inheritance with existing Java compilers.; We have modified a JVM to support multiple code inheritance. Our implementation does not affect the running time or the semantics of standard single inheritance Java programs and executes correctly programs that use multiple inheritance. |
