I have a habit of getting too many projects into a single Eclipse workspace and getting confused about what is where and for what. Frequently I need to reference JBoss quickstart or other existing code/projects and rather than have them imported into the same workspace as what I'm working on I decided that I wanted to run another instance of Eclipse and keep them in a separate workspace. I ran across this link on how to do that and it worked perfectly for me: https://blogs.oracle.com/dns/entry/opening_multiple_eclipse_instances_on. All that I needed to do was 'open -n /Applications/eclipse/Eclipse.app' and then select the other workspace with the reference projects.