Oracle has officially dropped x86 / I586 builds for all platforms back in September 2017 with release of version 9. The version 8 is officially maintained for one year, so there would be no more updates for it after September 2018. Till then everybody should jump to the newest version, which would be 11 at the time. They also adopted rapid release cycle, with a new version every 6 month and probably some LTS version. But the latest isn’t important for this topic.
The disappearance of the Oracle x86 build has at least two consequences. First of all there are no possibility to run Java software on the x86 system anymore. Funny enough I still know some people on the systems like this. Second issue: I use Language Tool for grammar check in the Libre Office, which is a Java-based extension. And one need the Java with the same architecture as the office itself. It isn’t possible to combine x86 office with x64 Java. Therefore, in current situation it wouldn’t be possible for me to use this Java tool in x86 office without a x86 Java. Probably there are some other Java usage scenarios here, portable browser for example, but I don’t know them, and I don’t know if x64 Java version is used in the x64 version of such program.
I see two possibilities here. There is a project on GitHub (ojdkbuild), which make Windows builds of Open JDK from the Red Hat sources, also the x86 ones. It is possible to use this as a basis for x86 portable Java builds. Probably somebody would also like to have a x64 version as an alternative for Oracle based portable version. If JRE is needed, we can probably create it from JDK by deliver only the modules, which Oracle delivered in their JRE. This is now possible, thanks to the new Java module system. Or we simply remove the module part blocks and only left the big combined modules file from JDK.
The other possibility (but we could also consider both variants to be achieved) is to create a x64 portable Libre Office. I know that on this site most people are skeptical about x64 software, but in this case this should be helpful.
I also have some thoughts and questions here. It is possible to extract the Libre Office from the MSI file. The Java builds are distributed as .MSI and .ZIP files. It should be possible to replace the x86 files with x64 ones in the portable app folder. This would be test enough for the usage of the x64 version. I already use portable VLC x64 this way Should I anyway check for some additional leftovers from the x64 version, which are not presented in the x86 version? Is the guerrilla field guide still the best description of the process with all recommended programs?