I discovered in looking at differences between the .war's produced by the Maven and Ant builds (over on
SOLR-3706) that the Ant-built .war contains cglib-nodep-*.jar and objenesis-*.jar under WEB-INF/lib/.
mvn dependency:tree says that easymock-*.jar depends on these two jars. In the Maven build, the solr core module depends on easymock-*.jar with test scope; as a result, none of these three jars are included in the Maven-built .war, since test scope deps are automatically excluded from the .war.
easymock-*.jar is not included in the Ant-built .war because solr/webapp/build.xml explicitly excludes it. These other two jars should get the same treatment.
Here's a patch to remove these two jars from the .war: