Commenting on Apple not shipping Java 6 with Leopard, John Gruber says Java isn’t an engineering priority for Apple and they decided to allocate resources elsewhere in order to ship an already delayed product. I quote an interesting part:

Several irritated Java developers suggested that I’d feel differently if it were a developer runtime that I personally cared about - that I’d be irate if, say, Perl or Ruby or Python were dropped or degraded in Leopard. But that’s not a good comparison; Perl, Python, and Ruby pretty much compile out of the box on Mac OS X. Apple doesn’t have to do much at all - at least relative to Java - to include them on Mac OS X. Why? Because that’s how these tools are designed and engineered - they’re made to “just build” on any Unix-like OS. It’s not Apple’s responsibility that Java isn’t like that - it’s Sun’s.

Err, if it is Sun’s responsibility, then why not let them ship Java! ;-)