java.lang.ClassNotFoundException throwing some error

java.lang.ClassNotFoundException: org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter

I added following jar files:

commons-fileupload-1.2.1.jar
commons-logging-1.1.1.jar
freemarker-2.3.16.jar
ognl-3.0.jar
servlet-api.jar
struts2-core-2.2.1.jar
xwork-core-2.2.1.jar