what is the jar for mks.util.MKSRollingFileAppender class?

I am trying to deploy the war file on 12.2, its working fine however facing issue with the log generation.

Error:

log4j:ERROR Could not create an Appender. Reported error follows.
 java.lang.ClassCastException: mks.util.MKSRollingFileAppender cannot be cast to org.apache.log4j.Appender 

So understanding is two Appenders are conflicting, and I am unable to find it.