What is "sablevm"

SableVM was a clean room implementation of Java bytecode interpreter implementing the Java virtual machine ( VM) specification, second edition. SableVM was designed to be a robust, extremely portable, efficient, and fully specifications-compliant (JVM spec, Java Native Interface, Invocation interface, Debug interface, etc.) Java Virtual Machine that would be easy to maintain and to extend. It is now no longer being maintained.

The implementation was a part of the effort in the early 2000s to break the Java ecosystem free from Sun Microsystems's control.