Unique identifier for a server process.

[Matthew Dornquast <ma...@cata.com>]

Java question:

How do I get a globally unique Identifier for an instance of a VM without relying on an external configuration?  Is there any way to do this without using JNI?

IP Address is a good start, as generally it's unique. (Yes, I know non-routable disqualify, but the scope is LAN related)  The challenge is what happens when two or more copies of a server are running on the same box.

This relates to something I'm doing with sessions for Tomcat.

Any help/suggestions appreciated.

-Matthew

Re: Unique identifier for a server process.

[Nimret Sandhu <ni...@lightmail.com>]

On Mon, 17 Jul 2000, you wrote:
> 
> Java question:
> 
> How do I get a globally unique Identifier for an instance of a VM without relying on an external configuration?  Is there any way to do this without using JNI?
> 
> IP Address is a good start, as generally it's unique. (Yes, I know non-routable disqualify, but the scope is LAN related)  The challenge is what happens when two or more copies of a server are running on the same box.
> 
> This relates to something I'm doing with sessions for Tomcat.
> 
> Any help/suggestions appreciated.

1 possibility is http://java.sun.com/products/jdk/1.1/docs/api/java.rmi.server.UID.html#_top_

however, i am not sure how well this will work .. if u can get a hold of the
java process ( write it to a .pid file from your startup script, if u have
one), then you could use that along with the ip addr, and perhaps port #.

hth ~
-- 
Nimret Sandhu
http://nimret.penguinpowered.com || http://nimret.dhs.org
http://www.360.com

Re: Unique identifier for a server process.

[Arion Yu <ar...@stt.com.hk>]

Hi!

I have an idea but don't know if it works.

for each VM,
while (true) {
try {
create a ServerSocket listening on a particular port;
log the current time (the identifier for the VM);
close the socket;
break;
}
catch (some exception) {
// try again after some time
}
}

Arion

Matthew Dornquast wrote:

> Java question: How do I get a globally unique Identifier for an
> instance of a VM without relying on an external configuration?  Is
> there any way to do this without using JNI? IP Address is a good
> start, as generally it's unique. (Yes, I know non-routable disqualify,
> but the scope is LAN related)  The challenge is what happens when two
> or more copies of a server are running on the same box. This relates
> to something I'm doing with sessions for Tomcat. Any help/suggestions
> appreciated. -Matthew

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