Then, simply install any plug-ins or features in to that extensions path, as opposed to into Eclipse directly. So, again, for Sysdeo, you might have:

c:\eclipse_extensions\eclipse\plugins\com.sysdeo.eclipse.tomcat_3.0.0\

The only remaining step will be to point your unique Eclipse installations to that extension location on first boot. To get an Eclipse installation to load an external extension location - Go to Help->Software Updates->Manage Configuration... :

... and then right-click and say 'Add Extension Location', giving Eclipse the path: c:\eclipse_extensions\eclipse .

( Note: Just pretend that 'eclipse_experimental' in the above picture is actually 'eclipse_installations').

It will ask you if you wish to reboot - for now just say no, and close Eclipse manually. That's it, now your Eclipse installation will load all plugins and features in that extension folder as if they were in its own plugins folder.

Workspaces

Workspaces are the last component I want to discuss - and creating new workspaces is as simple as changing your shortcut to Eclipse (or your startup-script). Workspaces are where you keep the code, and are also where you save your preferences (Java Editor settings, code formatting settings, colors, fonts, key mappings, etc). I'll continue the Windows theme here. First, create a workspace folder, such as c:\eclipse-workspaces\ . Next, create a shortcut to one of your Eclipse installations that references a subfolder in this new folder as part of the -data argument. So, rather than having c:\eclipse_installations\eclipse_31_M7\eclipse.exe as your startup command in your shortcut (or startup script or whatever), you would have C:\eclipse_installations\eclipse_31_M7\eclipse.exe -data c:\eclipse-workspaces\ workspace1 . Actually, while we're at it, we can make the memory allocation more reasonable. Here are three different startups with different installations and different workspaces that all use the same extensions folder (note, I have put these on multiple lines to make them easier to read):

c:\eclipse_installations\eclipse_31_M7\eclipse.exe 
  -data c:\eclipse-workspaces\workspace1 
  -vmargs -Xms256M -Xmx256M
  
c:\eclipse_installations\eclipse_30\eclipse.exe 
  -data c:\eclipse-workspaces\workspace2 
  -vmargs -Xms128M -Xmx256M
  
c:\eclipse_installations\eclipse_bleeding_edge\eclipse.exe 
  -data c:\eclipse-workspaces\workspace3 
  -vmargs -Xms256M -Xmx256M
  
c:\eclipse_installations\eclipse_bleeding_edge\eclipse.exe 
  -data c:\eclipse-workspaces\workspace1 
  -vmargs -Xms256M -Xmx256M

In the above example, workspace1 is running under Eclipse 3.1 M7, workspace2 is running under Eclipse 3.0, and workspace3 is running under some bleeding edge integration build. Finally, notice that I have also made another shortcut to workspace1 running under a completely different installation.

One final thing to note - a lot of users feel frustrated because their workspace preferences can't be shared from one workspace to another transparently (for instance, I use the same code formatter for multiple workspaces). There are some technical reasons why this isn't typically done, but there are workarounds. You can always copy the workspace folder and rename it to create another workspace. Alternatively, you can copy the .metadeta folder under one workspace, and paste it into another. These are 'black magic' ways to do this however, so do so at your own risk. The most appropriate way is to go to a particular workspace, and perform a preferences export. You can do this in 3.1 milestone builds by going to File->Export and selecting preferences - then select what preferences you want to export, and where you want to export them (e.g. c:\eclipse-workspaces\preference_backups\workspace_preferences_05-11-05.epf).

Then you just need to import to your other workspaces the same way. Voila!

Until next time,

R.J. Lorimer
rj -at- javalobby.org
http://www.coffee-bytes.com