I know it's silly and bad form to reply to my own post, but minutes after hitting the "Publish" button I found out that all I had to do was to point JLink to the correct location of the java executable. So, with the current versions of JDK 8, this gives:
Needs["JLink`"];
InstallJava[];
ReinstallJava[CommandLine -> "/usr/bin/java"];
and then after that everything works fine for me.