Those other languages that run on the JVM are not based on Java. They do not add another layer. They run on the same layer as Java.
They may be slower than Java nonetheless - because the JVM is designed for running Java.
They may be slower than Java nonetheless - because the JVM is designed for running Java.
Someone reported about a factor of 100 for java against Ruby. jython is only 50. But this is still so bad that I would not waste my time.
BRL uses Kawa Scheme, so the code is compiled to JVM bytecodes. The result is slower than C implementations of Scheme, but still faster than PHP.
I think it is desirable to give clients the best possible user experience and execution speed is indeed a valuable point, especially in the web.
A friend of mine still codes assembly if he feels its necessary. I 'am not that fanatic (in facts he is always making fun of java) - but, once you have used his number crunching algos, you'll never go back.