All of them were runnign since 4 days, had emerged ~6000 packages before, glibc was upgraded, then @ystem and @world w/o problems. dev-java/edtftpj-2.4.0 dev-java/snip-0.11-r1 dev-java/browserlauncher2-1.3-r2 dev-java/rundoc-0.11-r1 dev-java/javacsv-2.1
4 of 5 affected images were systemd images FWIW.
and masking jdk:1.8 and unmasking jdk:11 helps too - so for now I'll tinderbox here java packages only with the newer one
going to dupe into the newer bug since it has more investigation into the issue *** This bug has been marked as a duplicate of bug 807832 ***