Geneos - Newer Webserver / Web Dashboard versions are not compatible with Java 8

Newer Webserver / Web Dashboard versions are tested using OpenJDK Java 11.

If you try to use Java 8 you will get an error like below when starting the Webserver / Web Dashboard.

 Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/itrsgroup/server/WebAppServer 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

The above Java error is a generic message that means that the Java version that is being used to run the application (webserver in this case) is lower than the Java version that was used to compile the application.

Background:

A user wanted the webserver to use their own JRE which is Java 8 (1.8.0_351)

[myhost:/rmds/geneos/geneosws/JRE/bin]$ /rmds/java-linux/bin/java -version
java version "1.8.0_351"
Java(TM) SE Runtime Environment (build 1.8.0_351-b10)
Java HotSpot(TM) 64-Bit Server VM (build 25.351-b10, mixed mode)

Instead of the JRE that comes with the webserver which is Java 11.

[myhost:/rmds/geneos/geneosws/JRE/bin]$ ./java -version
openjdk version "11.0.17" 2022-10-18
OpenJDK Runtime Environment Temurin-11.0.17+8 (build 11.0.17+8)
OpenJDK 64-Bit Server VM Temurin-11.0.17+8 (build 11.0.17+8, mixed mode)

More info about Geneos' Java support is here - https://docs.itrsgroup.com/docs/all/geneos/6x-release/compat-matrix/index.html#java-support