Me too. But, Puybaret try few years ago to do this and the answer was something like "we don't care".
The java applications are write with and for a specific version; some instruction being deprecated or replaced in newer version of java.

Note: On Ubuntu 18.10 Sweet Home 3D works fine

If so, open an SH3D sesion, verify the java version You use (Help->About).
If is 9 or 10 try to import some furniture library and see if appear in catalog. In my tests they don't which mean don't work fine.
If You are interested I could explain You my way to make it usable (SH3D, editors and even AOI which work bather with jre6;7 or 8)