I forgot: This could also be a bug in javadoc/openjdk and not in elki. Note that the package also fails in stable:
https://tests.reproducible-builds.org/debian/logs/stretch/i386/elki_0.7.1-3.build2.log.gz If you reassign, please use "affects 923841 src:elki" so that this bug is still shown in the BTS page for elki (this should, in theory, help to avoid duplicates from other people reporting FTBFS bugs). Thanks.
