The problem from https://github.com/apertium/lttoolbox-java/issues/4#issuecomment-543759870 is now reality. OpenJDK 8 was removed from Debian. Oldest installable release is OpenJDK 11.
The problem from #4 (comment) is now reality. OpenJDK 8 was removed from Debian. Oldest installable release is OpenJDK 11.