unexpected exception: java.lang.NoClassDefFoundError: org/apache/log4j/LogManager

Question

I\'m developing a GWT application. It\'s using RPC to collect information from an internal system. It does so by using a library jar, lets call it alpha.jar. We are using th

Answer 1

org.apache.log4j.LogManager is a class from log4j 1.2 (not log4j2).

Therefore, one of your web app jars must be referencing it. The culprit should be visible in the stack trace.

Depending upon your circumstances, you may want to just add a log4j 1.2 jar to the web app as the two versions are completely independent of each other.