During the Struts initialization, it hits the following error messages.

SEVERE: Unable to initialize Struts ActionServlet due to an unexpected exception or error thrown, 
so marking the servlet as unavailable.  Most likely, this is due to an incorrect or missing library dependency.
java.lang.NoSuchMethodError: org.apache.commons.digester.Digester.parse(Ljava/net/URL;)Ljava/lang/Object;
	at org.apache.commons.chain.config.ConfigParser.parse(
	at org.apache.struts.action.ActionServlet.initChain(


This is caused by certain method is not found in the commons digester library. You need to upgrade your commons-digester.jar to latest version.

In this case, I’m using “Struts 1.3.10 + commons-digester-1.6.jar + struts-tiles 1.3.10” combination, and hits the above error message. After upgraded to the latest commons-digester-2.0.jar, the error message is gone.