I'm assuming some of it has to do with licensing agreements. My guess is carriers want to keep control of the code on the device because many preload their images with extra stuff ('crap' or 'value added service', ymmv).
Sun/Oracle can put out timely JRE/JDK updates for Windows/Linux - why doesn't Apple? Similar situation, and one which I thought was incredibly stupid for Sun to get itself in to years ago. If Java is really that core to your business (changing stock symbol to JAVA even!), don't let a third party control the availability and release schedule of that software for some of your users. Sun did it with Apple/Java, and Google's going it with multiple manufacturers and Android.
Sun/Oracle can put out timely JRE/JDK updates for Windows/Linux - why doesn't Apple? Similar situation, and one which I thought was incredibly stupid for Sun to get itself in to years ago. If Java is really that core to your business (changing stock symbol to JAVA even!), don't let a third party control the availability and release schedule of that software for some of your users. Sun did it with Apple/Java, and Google's going it with multiple manufacturers and Android.