From the Wiki page, if people are wondering why it never took off: > The published specifications are very incomplete, being only sufficient for writing operat

From the Wiki page, if people are wondering why it never took off: > The published specifications are very incomplete, being only sufficient for writing operating system code that can support a JVM that uses Jazelle. The declared intent is that only the JVM software needs to (or is allowed to) depend on the hardware interface details. This tight binding facilitates that the hardware and JVM can evolve together without affecting other software. In effect, this gives ARM Holdings considerable control over which JVMs are able to exploit Jazelle. It also prevents open source JVMs from using Jazelle. So it sounds like ARM tried (presumably) to leverage it to make some profit off of support agreements, but ended up falling on their own sword.