Open the application multiple times in the same instance

[nickkrause]

Hello,

we are creating a swing application, using the following standard code:

SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});

Every time we call our program, it opens a new application. If we call
it twice, 2 applications will be opened.
We want to avoid that.
That is, we call first our program, it opens the application once.
Then everytime we call our program again, it opens it in the same
previously opened application.

Do you know how to do that?

Thanks,
Nick

 

[Boudewijn Dijkstra]

Every time we call our program, it opens a new application. If we call
it twice, 2 applications will be opened.
We want to avoid that.
That is, we call first our program, it opens the application once.
Then everytime we call our program again, it opens it in the same
previously opened application.

Do you know how to do that?

There are several ways to do this. The basic idea is to register the presence
of the application when it first starts up. Subsequent application calls can
then check this presence. Because a new JVM might be created when a new
application call is made, a JVM-local registration is not reliable. Instead
you can consider to create a file at a known location or to open an IP port
bound to localhost.