On my MacBook Pro, I installed IDEA 9.0.1 CE. I tried to open a project. I have two JDK's configured: 1.5 and 1.6. This is on a Snow Leopard machine.
No matter what I do, I don't seem to be able to get rid of those red wavy underlines in the editor. Surprisingly all the unresolved classes are from the JDK. What is the way out? How can I tell the IDE to resolve the JDK classes again (if they are cached somewhere on the disk)?
Restarting the IDE does not seem to help.