Why does the Eclipse Package Explorer show the projects from two different workspaces on my Mac?

Question

I've discovered a curious thing on my Mac. At some point I apparently created two different Eclipse workspaces, one in /Users/username/workspace and the other in /Users/username/Documents/workspace (this may have happened as a result of some troubleshooting a while ago). I never knew until now that anything was amiss because the contents of both workspace folders are visible in the Eclipse Package Explorer.

I only just noticed because I'm trying to use Mercurial from the command line and couldn't find the project folder to create a repository. After some cursing I found the other workspace. The other strange thing is that from Eclipse's perspective, projects from both workspaces appear to be housed in /Users/username/Documents/workspace, even though some projects are only in /Users/username/workspace.

I believe the problem itself is easily solved (import things from one workspace into the other) but I want to understand why it is happening, and haven't been able to find anything about it elsewhere. My suspicion is that this is being caused by metadata that is telling Eclipse about the workspaces in both locations, and / or some Mac file system magic. However, I'm not sure where to start looking. Where I should begin? What might be causing this?

Answer 1

First, I personally prefer Eclipse to present me with a combo-box allowing me to select the workspace to be opened. You can set it in the preferences, under General -> Startup and Shutdown -> Workspace.

If you prefer not to be asked, you can specify the workspace explicitly in the eclipse.ini file (inside the Eclipse.app package) by using the -data switch (more about Eclipse.ini: http://wiki.eclipse.org/Eclipse.ini#Mac_OS_X_Example, all the switch options are in the Eclipse help).

Projects are not required to be inside the workspace. I like storing my work outside the workspace, since I usually share projects between workspaces. When creating a project, you can specify a location which is different than the default location. You can see the location of the project by right clicking it in the Project Explorer and selecting Properties.