Let me take back my words.
JDeveloper on OSX is useless for PL/SQL programming. Attempt to compile a simple procedure will crash the JDeveloper. Now I am back to using SQLPlus. Is there any tool, preferably free, that works well on OSX for PL/SQL?
After posting, I remembered that I am using Apple's JDK 1.5. Maybe JDeveloper doesn't work so well with 1.5, I thought. So I switched to JDK 1.4.2_08 from Apple and sure enough, it crashes no more.
Now if you excuse me, I have got some triggers to write.