Dear maintainers, I have a fix for this bug (by copying in the relevant files from OpenJDK 9) at https://salsa.debian.org/java-team/icedtea-web/merge_requests/5
It is a hack, but from my testing it works. I hope this is helpful; I would like to see this package stay in Debian Buster. Cheers, -- Michael R. Crusoe
