Integrating OIDC into your Existing Webapp fails with error this version of the Java Runtime only recognizes class file versions up to 52.0

[jkjha]

Describe the issue:

As per the document here:

Extract the downloaded lib.zip file to the <APP_HOME>/WEB-INF directory. (If you already have a lib folder in your web app, merge the content of the downloaded lib.zip file into the existing lib folder.)

I downloaded lib.zip, converted it to jakarta namespace and copied the libraries to my existing webapp. But after that tomcat started complaining about the error:

        java.lang.UnsupportedClassVersionError: org/opengrok/web/WebappListener 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.opengrok.web.WebappListener])
                at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2515)

How to reproduce:

1. Get the opengrok war file from here: https://github.com/oracle/opengrok/releases/tag/1.7.35
2. Copy the source.war file to webapps directory. Now the UI is accessible at localhost:8080/source
3. Download the lib.zip from here (for oidc): lib.zip
4. Now convert this to jakarta namespace using the conversion tool mentioned here: https://github.com/apache/tomcat-jakartaee-migration
5. Now copied the content of lib.zip file to webapps/source/WEB-INF/lib/ folder.
6. Restart tomcat.

Expected behavior:
Tomcat should be able to start after coping the file.

Environment information (Please complete the following information; remove any unnecessary fields) :

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[jkjha]

Sorry for spam. There was some issue with my OS version it seems.