Re: Do I get Physical Thread in Java?

From:
Patricia Shanahan <pats@acm.org>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 20 Aug 2006 20:21:10 GMT
Message-ID:
<Wu3Gg.11013$0e5.576@newsread4.news.pas.earthlink.net>
zero wrote:

"Mike Schilling" <mscottschilling@hotmail.com> wrote in
news:VX1Gg.11618$kO3.5975@newssvr12.news.prodigy.com:

dimitrik107@hotmail.com wrote:

When you write Thread t = new MyThread(); r.start(), do you get a new
thread (you know like in Linux you call pthread_create() and kernel
gives you a new thread for running). Maybe java is optimizing and JVM
will not call pthread_create when you new your thrread?

If anyone know, please explain; thank you.

This is up to the JVM implementation. The Java standard decribess how
threads behave, but whether they're implemented with OS-level threads,
a lightweight threading package, or by having a single-threaded
interpreter round-robin among the active threads is left open.


Furthermore, the whole point of java is not having to worry about stuff
like this. If you do, you're probably either using the wrong tool (try
C++) or going about your problem the wrong way. There may be legitimate
reasons to rely on this information in java, but I can't think of any.


What about programs that need more than one second of CPU time per
second of elapsed time? Multiple OS threads can run on different
processors at the same time. A single OS thread can never get more than
one processor.

Patricia

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