One new "hidden" feature of JDeveloper 10.1.3.1 is the "run with compile errors" feature. It allows you to run your project even if you have compile errors in it. This makes it easier to test code that is not yet complete or that depends on other people source which is incomplete. In general it makes test driven development easier.
To set this go to your project properties under the Run/Debug Configuration -> Tool Settings and check the box.
If you like this feature you can thank the guys at one of the big 5 consulting companies, who decided to switch their teams from Eclipse to JDeveloper and requested that we implement this feature.
(They weren't the only one asking for this - I remember people approaching me about this before in an event we held).
So there you go - one more reason to get out of the Eclipse shadow and into the bright world of JDeveloper.