KeyCloak Server Caused by: java.lang.ClassNotFoundException: java.security.acl.Group

Question

I\'m running a KeyCloak server to authenticate users who would like to gain access to a Spring Boot/Spring Web REST API. However, an error occurs while trying to authenticate.

Answer 1

After some research I found the answer to my problem.

The problem is that java.security.acl.Group is being deprecated since JRE 9 and marked for removal in future versions.

java.security.acl.Group is being replaced by java.security.Policy

I was running my Spring-Boot application on JRE 14 in which this class appeared to be no longer available.

So once I changed my Spring-boot application (which hosts the REST-API) to use JRE 11 the error went away.

Note: The pom.xml Java version attibute 11 needed to change as well as the JDK in the build path in Eclipse (which is the IDE I'm using) JDK Buildpath