include element tells the framework to load the
struts-default.xml, which it wil will find in the
struts2.jar file. The
struts-default.xml file defines the "standard" interceptor and result definitions.
You can put your own <include> elements in your
struts.xml interchangeably with <package> elements. They The configuration objects will be loaded in the order of appearance. The framework reads the configuration from top to bottom and adds objects as they are referenced.
A "module" can be added to an application by placing a
struts.xml and related classes into a JAR on the classpath. FreeMarker and Velocity templates can also be provided by JAR, making it possible to distribution a module in a single, self-contained JAR that is automatically configured on startup.