Yeah, Java’s a bit of a pain.
You have to deal with the manual downloads for each Java release, you have to deal with both the x32 and x64 fixlet structure, you have to deal with two different fixlets for each architecture (one for “system has an earlier JRE 8” and another for “system has a JRE earlier than JRE 8 (7,6,etc.)”.
Also, the JRE installers do not remove older JREs, so they would still be available on the system and taking up space; so there are two additional fixlets for “Multiple JREs detected” (one for x32 and another for x64), that remove all but the most recent Java.
There’s a fixlet somewhere, I think in BES Support, that will let you set up a local Java distribution point. Then you can download the JREs and put them in that location, without having to rename them to match the sha1 and precache them into bfmirror/downloads/sha1. This also helps ensure that the automatic cache cleanup doesn’t remove the installers when they age out of the sha1 cache. I haven’t used that functionality yet though, I just keep a huge sha1 cache.