Recent releases of libbluray 0.6.0, libaacs 0.7.1, and libbdplus 0.1.1 have improved the overall situation for open-source / Linux Blu-ray support. In particular, the big Blu-ray library update is the first that makes BD-J -- the Blu-ray Java interactivity layer -- usable to end-users. The Blu-ray Java code will work with both OpenJDK and the Sun/Oracle JDK releases.
The libbluray support is working to the extent of being able to use a USB-based Blu-ray drive on a Raspberry Pi board in conjunction with the VLC media player.
More details on these open-source Blu-ray development updates can be found via Jean-Baptiste Kempf's blog.