Real-Time Java™ Platform Programming

Write Once, Run Anywhere—Maybe

In some respects, the JVM specification has done an admirable job. All the basic operations do the same thing on every correct JVM. That is not a small achievement; for instance, every processor or floating-point support library seems to have slight differences in the way it implements floating-point arithmetic. Even implementations of IEEE standard floating point turn out to be subtly different. The JVM puts a consistent interface over such differences. Simple programs run, and give the same results, on all JVMs.

Parts of the specification for the JVM are peculiarly loose. The specification seems to be a compromise between strict specifications to support portable code, and loose specifications to make it easy ...