Minor Description
Its a bit confusing with the installer:
OpenMeetings 5.x requires Java11, but when running the startup.sh script it will tell you first: Minimum version is 52 (which is java8)
Using CLASSPATH: /home/openmeetings/apache-openmeetings-5.0.0-SNAPSHOT/bin/bootstrap.jar:/home/openmeetings/apache-openmeetings-5.0.0-SNAPSHOT/bin/tomcat-juli.jar
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/catalina/startup/Bootstrap : Unsupported major.minor version 52.0
Cause that is the minimum version for the Apache Tomcat server that OpenMeetings is packaged inside.
But if you try java8 it will just not startup with:
07-Jun-2020 05:34:40.770 INFO [main] org.apache.catalina.core.ApplicationContext.log No Spring WebApplicationInitializer types detected on classpath 07-Jun-2020 05:34:40.772 SEVERE [main] org.apache.catalina.core.StandardContext.listenerStart Error configuring application listener of class [org.apache.openmeetings.util.OMContextListener] java.lang.UnsupportedClassVersionError: org/apache/openmeetings/util/OMContextListener has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0 (unable to load class [org.apache.openmeetings.util.OMContextListener])
And it will actually not create above logs, unless you manually edit add some logging.properties as it won't even start the logger context.
But in fact OpenMeetings require Java11.
This could be probably be improved to just clearly make Java11 minimum requirement and fail right from the start with binary version 55.0 error.