Does anyoneknow why they used Java? To create Java programs for each movie is a nightmare I'm sure. Did they consider XML? or other light weight options?
Java is a way, way more powerful language than any thing else used in disks. What you can do with it is almost limitless. Having said that I have yet to see a really killer app done with it yet. The other thing about java is it is cross platform meaning you don't have just one company that is the gate keeper and can charge what ever they want because they have the monopoly. You can also use what ever processor you want. That is key as more green laws come in. The Arm processer has a very low power draw for example so would be good for devises going into California. You might pick a different processor if you cared more about CPU power and less about power drain.
As for things being a night mare it depends. If you are creating a game then yes it will be a nightmare. But if you look at some thing like U-Control I am sure they have a U-Contol class that they just import, change the skin if they want and they are out the door. It took some time and money the first time but then it is just reusable code after that. I would expect to see third party programmers/companies creating classes that do certain things, you just import the jar file into your project add a small bit of code and you have it. I don't think they have really gotten rolling on this yet and I also don't thing the killer apps will necessarily come from large studios at first. It will take some where smaller where more independent thought is encouraged.
Some thing to remember about load times is that most of that load time is getting stuff off of disk not crunching it through the processor. Ya a $40 DVD player has a 40X drive in it these days but the first DVD players didn't. Same thing with BD as we go along the drives will get faster and the load time will go down.
BTW it isn't mandatory to use BD-J. My guess is the newer stripped down Warner disks like Pelican Brief and a A Time to Kill have decided not to use BD-J.
But back to the original topic. My opinion is BD Live has always been about selling downloads. Period.