Just as a note to myself and to any other user:
If you have Oracle Java installed and you switch from Yosemite to El Capitán, you may install the new Java 6 for OS X (needed e.g. for OpenOffice – do not ask why – but also for some Java apps).
CafeTran – at least in my case – keeps using Oracle Java. I really assumed that reinstalling Java 6 would mess up things.
UPDATE: I downloaded a Java app, and of course it told me I needed Java 1.6 (OS X version) to be able to run it. I did, and there don't seem to be any problems. The app ran, and so do CT an LO.
Torsten: needed e.g. for OpenOffice
I finally installed El Capi. No problems with LibreOffice:
I also only use Java 1.8. So far, everything seems to work fine, with the exception of a few plug-ins.
Main disappointment: The split screen doesn't move the Menu for the right-side app.
I don't know about OOo, but LibreOffice runs fine here, and so do all other Java apps here. I only have 1.8 installed:
Hans-van-den-Broeks-Computer:~ hans$ java -version
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)