Unable to load config class org.apache.struts2.interceptor.debugging.DebuggingInterceptor

Algo asi:

WARN - InterceptorBuilder.constructInterceptorReference(60) | Unable to load config class org.apache.struts2.interceptor.debugging.DebuggingInterceptor at interceptor - jar:file:/D:/work/.metadata/.plugins/org.eclipse.wst.server.core/tmp1/wtpwebapps/pxw/WEB-INF/lib/struts2-core-2.0.8.jar!/struts-default.xml:76:115 probably due to a missing jar, which might be fine if you never plan to use the debugging interceptor

Problema: enlace struts-spring, hay un file con properties de struts http://cwiki.apache.org/WW/strutsproperties.html
donde se explica algo.

Solución: en struts.properties se comentó la linea:
#struts.objectFactory=spring