Implementing an E cient Java

The Java virtual machine (JVM) is usually implemented with an interpreter or just-in-time (JIT) compiler. JIT compilers provide the best performance, but must be substantially rewritten for each architecture they are ported to. Interpreters are easier to develop and maintain, and can be ported to new architectures with almost no changes. The weakness of interpreters is that they are much slower than JIT compilers. This paper describes work in progress on a highly eecient Java interpreter. We describe the main features that make our interpreter ef-cient. Our initial experimental results show that an interpreter-based JVM may be only 1.9 times slower than a compiler-based JVM for some important applications.