It appears that they need to decide on ONE version of Java to base the encoding on, as there does not seem to be this one version of JAVA used by all parties. That would be the first step to solving the incompatibilities with BD-Java IMO. The next step is to freeze the Java version as well as differing encoding methods used, soon like they did with SD DVD so there will not be continued compatibilities issues.
That would only leave the dynamic DRM that needs a solution that keeps the studios & BD player mfg both happy. Some kind of universal DRM update system is what is needed so that regardless of the player the update is the same so that one update can be put on the BD movie disc it is first used on and will work with ALL BD players. Then the studios who are the ones who require the dynamic DRM will be responsible for the cost of updating all BD players.
Do we really expect these BD player mfg to keep providing updates 5-10 years later for the hundreds/thousands of brands/models that will be out by then? I sure hope so but it will be a daunting task and likely end up costing more than the cost of the BD players in another year or so, and they need a plan to handle it.
Heck I still have my first SD DVD player being used in my younger daughter's room that is 10 years old and it plays all SD DVD movies still. Will we be able to say that with BD players?