Maybe someone knows?.. (Может кто-то знает?..)

but the java thing is not so stright forward as I thought earlier.
Open Office will look for that java in common files on the stick, so there all is fine.

Your opera will look for java in some windows default positions. Poiting it to the portable java, probably the java launcher will be neede to be run, this will then probably tell the system where the java is located (namely on the stick in such case).

So try to run the java starter first and see if the opera respond correctly. When I am doing such tests, I often simply zip the java folder on the hard drive and try then if java based apps will work.

https://portableapps.com/apps/utilities/java_portable_launcher