For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:logging/openSUSE_Tumbleweed/security:logging.repo
zypper refresh
zypper install jruby
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:logging/15.5/security:logging.repo
zypper refresh
zypper install jruby
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/security:logging/15.4/security:logging.repo
zypper refresh
zypper install jruby