I wanted to report a strange issue faced installing mendelson_opensource_as2_1.1b57 on CENTOS 8.
I first installed openjdk 11 via yum command. This resulted in the installation of openjdk version "11.0.8 2020-07-14 LTS".
After that, the setup of Mendelson goes fine, but the client GUI does not start. A window appears saying "Connecting to localhost/127...." and stays like that forever.
I can telnet to port 1235 locally and from remote without issues, but the JAVA client seems unable to connect.
I therefore installed an earlier version of openjdk ("11.0.1" 2018-10-16) and with that I could launch mendelson without issues.
I don't know if someone has a better idea of what could be the cause, but hopefully this workaround can help other people for now.