Single instance java application

Hi all,
I need a small help.i am working in java GUI Based program with Swings and in a form i have one button("print"). when i click on that button a batch file will execute and batch file screen will open.
for eg: if i started yahoo messanger only single instance is going to be created
if at all i am try ing to click print button again another window is opening. i need to open existing window on the tool bar or else print message like "already running"
so possibly send any java code if u have or send nice idea to do
Thanking you in advance,
Regards,
Rama.

phdk wrote:
Use threads. and use isAlive().
[http://java.sun.com/docs/books/tutorial/essential/concurrency/]
Rubbish
Open a ServerSocket on a particular port, and if your app starts up and opening that socket fails, you know you've already got an instance running

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Hi Ankit
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Single instance java application

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