I am looking into if there were any changes with log4j between 1.2.12 and 1.2.13. The official Tomcat binary is compiled with 1.2.12, and we are compiling against 1.2.13.
log4j used a trick to retain binary compatility whilst altering a class
hierarchy sometime around then. JCL must be compiled against the right
version of log4j or errors such as the above occur.