Since mid-2011 (when Gary Benson, the original author of Zero/Shark) left Red Hat's Java team), the Zero interpreter and Shark compiler have been basically unmaintained. A few months ago I picked up the project and fixed the outstanding issues (related to changes in Hotspot and LLVM) and started implementing a couple of significant improvements.

This talk will give a short summary about what Zero and Shark actually are, how they work, why they are relevant (even in the face of upcoming full ports for PowerPC and others), how it fits in the OpenJDK ecosystem, and then describe some of the more interesting details about what I did, in particular improved support for atomic operations, JSR 292/invokedynamic, interesting optimizations in both the compiler and the interpreter and more. Hopefully I will be able to present some interesting ports to other platforms like ARM or PowerPC, some benchmarks results as well as results from testsuites (TCK?). Finally, I'll give an outlook to the future, things that need to be done, open improvements, optimizations, etc.