When you run JDeveloper on Windows Vista you might run into several security issues. Sometimes the only solution is to turn off UAC (User Account Control). For me, it was best to install JDeveloper into my own user space, also add javadocs locally there and change the library lookups.

But at some point I was unable to create a new Java class file (on a package, right-click and select ‘new’). This was odd. After some thinking I decided to change the look and feel in the preferences back to ‘Oracle’ style instead of ‘Windows’ style. And indeed, rare but true, it worked again! UAC could be turned on again.