The Java bytecode language is emerging as a software distribution standard. With major vendors committed to porting the Java run-time environment to their platforms, programs in Java bytecode are expected to run without modification on multiple platforms. These first generation runtime environments rely on an interpreter to bridge the gap between the bytecode instructions and the native hardware. This interpreter approach is sufficient for specialized applications such as Internet browsers where application performance is often limited by network delays rather than processor speed. It is, however not sufficient for executing general applications distributed in Java bytecode. This paper presents our initial prototyping experience with Caffeine, an optimizing translator from Java bytecode to native machine code. We discuss the major technical issues involved in stack to register mapping, run-time memory structure mapping and exception handlers. Encouraging initial results based on our X86 port are presented.