Single Instance

[Kallen 0]

I am trying to make sure only one copy of my java program is running at a time.

After a quick search I came across the "lock file" trick...

FileLock lck = new FileOutputStream(flagFile).getChannel().tryLock();

if(lck == null) {

   JOptionPane.showMessageDialog(this, "A previous instance is already running....", "Settings",JOptionPane.WARNING_MESSAGE);

   System.exit(1);

   }

This works fine as a jar, but when I compile it using Jet 3.6 it stops.

Any suggestions?