Will Java 6 on Leopard has improved Performance

[Doug]

So (sic), Leopard doesn't have Java 6 (yet) which is V disappointing -
obviously. In fact I'm pretty pissed...!

Anyway, my question is to those who have a far better understanding of
this inner workings of Java than I is, can we actually expect
performance improvements in Java 6 on Leopard.

I understood the performance improvements were gained is register
allocation tricks down in the bowels of the VM. If this is the case,
is it part of the Java 6 spec and so can be expected in all
implementations of Java 6 - OR is it just the result of Sun's
implementation and so not necessarily carried over to other
implementations, eg. Apple's version.

[Brice]

Well, if you're only after performance improvements, and you have a
chipset to support it, the 64-bit VM in Java 5 on Leopard may help
you. While Java 6 did not in fact make its appearance (I, too, am
disappointed, but mostly in trying to understand what this means for
the future - maybe Joe can shed some light in the next podcast), but
the 64-bit VM is present, and that's pretty cool (though possibly not
terribly useful for many).

-Brice

[Christian Catchpole]

I cant see why any optimizations would not apply to apple or any other
OS on x86. This is as assumption, but i think a valid one since the
JIT is all about the CPU, not so much the platform.

[robogeek]

Christian..

It depends on how much of Sun's implementation is used by Apple in
their implementation.

The platform spec doesn't talk about performance. It doesn't talk
about implementation details such as register allocation tricks in the
VM or even whether the bytecodes get compiled to machine code or
whether the bytecodes are simply interpreted.

Probably Apple is going to use Hotspot as the VM rather than writing
their own VM. Hotspot undergoes performance improvements and tuning
in every relase.

But Apple would be free to write their own VM.. just as they felt it
important to implement their own GUI system rather than reusing X11's
as has many other Unix vendors. If Apple were to write their own VM
then Hotspot improvements would not automatically be inherited by
Apple's VM.

- David Herron

[Christian Catchpole]

Agreed, but another assumption of mine was that apple does use Sun's
VM. :) They have come so far with the JIT it would seem silly not
to. I assumed (again) that all the major JVM vendors on intel take
the latest Sun version and attach their value adds.

[Doug]

Thanks for the reply guys.

The missing piece for me was that Apple would use (or currently users
as suggested) Sun's VM. I had just assumed Apple would have had to
implement the whole VM themselves, from the ground up...

Cheers Doug