I has recently handed a truckload of client code all developed in Netbeans. In order to get a feel for the interdependencies, I thought I just fire up a clean copy of Netbeans and open it up. Unfortunately, when I tried to open the project I was greeted with the dreaded "unrecognized project; missing plug-in" dialog:

Hmnmm... That's ok, so I thought I'd just open it up as a "free-form" Netbeans project, but that's no good either, since Netbeans complains that it's already a Netbeans project! After a bunch of mucking around, I found out the problem, I was missing a plugin! But which one?

If you open up the nbproject/project.xml file will have something like this:

    org.netbeans.modules.j2ee.earproject
     ...

So that type element gives you the skinny. In this case I was missing the EAR project plugin. Once that was installed, the project opened up just fine. Thought I'd blog it up to save you some google time down the track.

Happy recognised projects!