Howdy -- I use the Mac (currently Panther) on a G4 Titanium to do everything. We did encounter one problem... running J2EE. A bug in the Reference Implementation of J2EE 1.3.1 (Linux distribution) works *fine* on the Mac, but shows up on other systems. So in that case, as I remember from the old days, things are almost always more likely to *work* on the Mac, so yes, always test on other environments. Write once - test everywhere. You also have to always know exactly what is supported and what is optional, too. I think there might be a few potential issues with Javasound and the availability of software instruments in the midi stuff. But those are the only two things I can think of right now. I'm sure if I were doing things that needed access to native hardware (3-d games, etc.) I might have run across far more issues.
We run
Tomcat 5 for JSP/Servlets, and everything's just as you expect.
My big complaint now is with J2ME development. That seems to be a Big Problem on OS X (big meaning "no support"). You cannot run MIDP 2.0, I believe. And the fabulous Wireless Toolkit from Sun just won't run on OS X, because a small piece of it is apparently native (go figure!) However, I do have it working under Virtual PC -- but really really slowly.
I'm considering buying a cheap PC JUST to run the wireless toolkit, but I sure hate to do anything on a PC rather than my Mac.
At MacWorld a couple of weeks ago, I met the guy who is in charge of Java for Apple, and of course I made my complaints about J2ME known (along with Dan Steinberg, editor of java.net, who also made *his* complaints known). A lot of people seem to want J2ME development on the Mac -- it's such a natural place for writing games!!
Anyway, a huge chunk of the engineers at Sun use Macs for development now. The specification lead for either
Servlets or
JSP (can't remember which guy) develops on the Mac. At the development of the new certification exam for servlets and JSP (the new SCWCD), HALF of the engineers in the room were on Macs. Contrast this with four years ago when I came to work for Sun, and had to keep my Macness in the closet. With OS X, I "outed myself".
A few uber-geek Unix heads who now use and love Macs includes James Gosling, Tim O'Reilly, and I think Bill Joy. But I know there are other famous geek switchers.
The Apple Java guy was very committed to supporting Tiger on a good (didn't define "good") schedule, but there seemed to be much enthusiasm there. Wow! This is so different from just five years ago when the Java development team for Apple had been reduced to 1/2 person. That's right, one guy, part-time was the entire Java group at Apple, from what I could determine at that time.
cheers,
Kathy
hopeless Mac enthusiast
Looks like you started a new thread for your question here. 'Round these parts we try to discourage duplicate posts, that way you and the folks that answer you can meet up in just one place. 
