Netbeans IDE. Cannot remember one serious crash. Have emptied the cache twice that I can think of over the years I have used it. (And most importantly: I have less problems than my colleague who uses IntelliJ.)
Also as others have mentioned I've had major stability problems with eclipse, mostly in connection with the perforce plugin.
As I have pointed out elsewhere sometimes some piece of software isn't a good match for someone.
Me personally I don't like Mac OS X or Ubuntu Unity. I don't say they are bad but I will make an effort to avoid having to use them. (And I can tell you why.)
I can clearly see how some people might have similar issues with my favourite software.
That said: if last time was a few years ago and you youch upon Java code again you could give it another try; maybe it works better on a modern machine?
I'm using PHPStorm and wanted to give Netbeans a try since my coworker liked it alot and I wanted to try it out anyways. Well opened it and tried to open a project folder (on windows), while navigating through the directories I accidentally clicked on network and it instantly frooze. Waited for like at least 10 seconds nothing happened. Closed it, never opened again...
It might be Netbeans, or it might be Java EE as a language, but that's the opposite of reliable. Stuff breaks when you breathe on it and is often fixed by something like deleting your Netbeans cache folder or just restarting Netbeans (after you've been hunting a Java bug for 2 hours). The most common phrase in class as people try to use this for a semester-long fourth-year programming project: "I didn't change anything, this worked yesterday when I went home!"
Also as others have mentioned I've had major stability problems with eclipse, mostly in connection with the perforce plugin.