well for a contrarian view (correct me if I'm wrong) besides OS X, I don't know of any other OS other than Solaris that actually ships with Java or includes it with the OS's updates.
Neither Windows nor Linux does this (or has this changed since Java went open source?). Both users and developers on those platforms have to download java separately (unless the OEM PC maker has a deal with Sun).
Not to mention that most companies that use Java, typical stay one version behind the latest one anyways, to make transition from one version to another as painless as possible.
And OSX never shipped in line with java versions - it has its own schedule of course. I don't know what all the fuss is about. People can still run what they run now.
I guess the issue is that there is no Java 6 you could install on Leopard. For other platforms Sun has been the provider of Java, but for OS X Apple provided it themselves.
Seriously, perhaps Apple is trying to discourage people from developing MacOS applications using Java in order not to make the whole experience appear slow. Their OS is already quite inefficient (which, BTW, makes me wonder why on earth anybody would make a Mac their development machine).
Macs make good development machines if your production machines are also UNIX based. Even if my code is truly platform-independent, I still find it easier when I don't have to mentally switch back and forth between windows and unix. Of course, I also find Unix to be a much more powerful environment. That said, I also haven't found speed to be a problem on my mac (it is slower than the windows laptop that my work gave me, but it's also an older machine).
Of course, this only addresses Mac vs Windows - the argument becomes less compelling if you're comparing it to linux. I'm not sophisticated enough with Unix to appreciate the differences between linux and bsd, but I do like the Mac UI, and unlike windows, I get a unix prompt, which is pretty tremendous.
D-Zone has been plagued with the most pathetic whining I've seen on blogs for a long time. STFU already, it's going to be coming. Soon.
PS. Isn't this Sun's responsibility anyways?