File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Java in General and the fly likes Only one application in the Memory Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Java » Java in General
Bookmark "Only one application in the Memory" Watch "Only one application in the Memory" New topic

Only one application in the Memory

M.K.A. Monster
Ranch Hand

Joined: May 02, 2002
Posts: 130
Hello Everybody,
I am building a desktop application. The thing is that I don't want 2 references to the program in the memory, so the 2nd time the program tries to start it just doesn't start.
I though of the following not working solution:
Create a starter-class.
This class should load the main-app class, built as a singleton.
This didn't work, I think that every time the application is loaded, it will get a amount of memory, and isn't allowed to look into the other applications memory.
Does any have a solution to this problem?
I have been thinking about setting a flag using Preferences, and reading this out. But I think that when the application crashes or something like that, and the value isn't put back the way it is done when it is closed, the application couldn't be started anymore.
Does someone have a better solution?
Mark Monster
Michael Morris
Ranch Hand

Joined: Jan 30, 2002
Posts: 3451
One trick (and I say trick because it is not an elegant solution) is to use a known system resource. The easiest is probably to open a on an unused port. Then if the application is loaded a second time then a BindException will be thrown when you try to bind the ServerSocket to the port. For example:

Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction. - Ernst F. Schumacher
I agree. Here's the link:
subject: Only one application in the Memory
It's not a secret anymore!