Re: Looking for Java process library
Kai Schlamp wrote:
Hello.
I am looking for a good way to list operating system processes from
within a Java application. There is a lot of information on the web
already. But most come up with running an external program, like "ps"
or "tasklist", and parsing the result.
Is there a Java library available that helps doing this in a system
independent way (no matter how it does it in the background)?
Another option, when one is only interested in Java processes, is to
use the LocalVirtualMachine class of jconsole.jar. The problem is that
it depends on tools.jar, which is quite large (12 MB), and I don't
like the idea to ship my product with such a huge dependent library,
just for fetching a list of running processes.
An ideas?
Two points in addition to those already raised by others:
First, the notion of what a "process" is varies from one O/S to
another. If you ask Windows and Unix and ZOS and OpenVMS to list
their "processes" they'll probably all give you some kind of list,
but the "things" listed will be qualitatively different: Something
that appears on one system's list would not meet the definition of
"process" on another system, and vice versa.
Second, on some systems the list will be out of date by the time
you get a chance to inspect it. Unix systems in particular use a lot
of very short-lived processes. (I saw a little demo the other day in
which all process launches were traced. The demo ran "ls" in a window
to list the current directory, and Unix ran *two* processes. One was
"ls," as expected -- and the other was "hostname," which the shell ran
as part of building a prompt string after "ls" finished.)
If you just want to "list the processes" in the manner of "top" or
something, and can deal with the fact that "process" means different
things in different environments and that the list may be outdated,
fine. But if you're trying to solve some deeper problem like "Is my
HTTP server still running?" there may be better approaches than
trying to find the HTTP process in a list of all processes.
--
Eric.Sosman@sun.com