Problems with running different processes by different users

[fomilya]

We've made a runnable jar and given copies of it to different users on one computer (working on two desktops). But only one of them can run the program at a time. When the second tries, the new process starts and dies immediately. But we really need two and more users working with SH3D at the same time.

Is there anything we can change in code of the program to solve it?

[Puybaret]

If you don't want to use the Single Instance Server, just comment the lines (or add a condition) in the addSingleInstanceListener, removeSingleInstanceListener and callSingleInstanceServer methods of the StandaloneSingleInstanceService inner class of SweetHome3D main class.
Note that if you disable this feature, you won't be able to copy paste items between launched application instances.
Please, explain why you want this behavior. If it's interesting, I could add a system property to disable the Single Instance Server.

[fomilya]

I've made a mistake: in our situation two users try to launch the program as an administrator. So eventually the program couldn't run twice from one user (administrator).

However, you've given an exhaustive answer. We will try to do what you suggested. Thank you.

Now I'll try to explain our situation.
We made SH3D save all projects in a single folder, regardless of the user-selected location. We closed the folder from designers working in SH3D as a safety measure. But since SH3D must save the project in our directory, and designers need to somehow re-open the project, we have created a shortcut for the program that runs it as administrator. This led to a loss of the ability to run a program to multiple users simultaneously.