Re: Help me!! Why java is so popular
raddog58c wrote On 02/06/07 19:03,:
On Feb 6, 4:41 pm, Mark Thornton <mark.p.thorn...@ntl-spam-world.com>
wrote:
[...]
Rubbish. You can do quite a lot of useful work with the JVM 'using' only
8MB or less which is trivial in the context of 1GB memory. I've been
running a service, written in Java, which has no noticeable effect on
the responsiveness of my normal applications. It sits there all day
doing its stuff and I can easily forget that it is still running. My
machine is a 4 year old 3.06GHz Pentium with 1GB of RAM.
No doubt, and Java's fine messaging implementation and rich set of
protocol support, eg, makes it a good vehicle for such things. A
service I'm fine with -- a utility I need to fire up over and over,
not so fine with that. I wouldn't write that in Java.
One point you're missing (and it doesn't seem you're
alone) is that there is no need to shut down the JVM after
your "utility" is finished. You can just leave the JVM
sitting there, already warmed up and ready to go, just
waiting to be told to load another class.
As a concrete example of this approach, consider a
browser running a sequence of applets, one after another.
How does one get Java to run faster than a compiled language? It
would seem there has to be a catch or specific circumstances for that
to occur, because it's hard to fathom how that could be the case.
The only actual data I've seen on this topic is now
quite old, dating from the first few years of Java. IIRC
it was an article in CACM, describing an experiment in
which several dozen computer science students wrote programs
using various languages: Java and C++ and C (I think). The
programs were then assessed for correctness and performance.
The average performance of the Java programs (I forget how
they defined "average" and "performance") was poorer than
that of programs in the other languages, *but* the variation
between languages was much smaller than the variation between
individual programmers. That is, performance depended much
more on programmer skill than on language choice. So the
answer to your question "How does one get Java to run faster"
may simply be "Write better code."
I believe the article was from an age before JIT, back
when Java really was a purely interpreted language. I don't
know whether the experiment has been repeated with more
recent implementations.
--
Eric.Sosman@sun.com