What does it mean to be about 1.6x Java's performance? Can you be specific - it doesn't seem to mean much since its implemented on the JVM. Also, I've been using it recently and "dog slow" is how I would describe it.
Roughly performance tests have shown: Java Performance (ms) * 1.6 = Compiled Rhino Performance (ms). So Rhino is about 60% slower than comparable Java code if you compile it to byte code on average.
It means algorithms runs 1.6x faster within Rhino. A JVM implemented in Rhino that runs Rhino within the JS-JVM will run even faster - roughly 2.56x faster.