WebSphere 5.1

Be sure to install WebSphere's Fix Pack 1.

WebSphere 6

See forum thread: http://forums.opensymphony.com/message.jspa?messageID=119574#119574

It looks like there is a bug in WebSphere App Server related to which classloader is used at the time that Struts2 is loading the properties files, (all properties files, not just struts.properties and default.properties). The bug may have been fixed in WAS 6.0.2.9, (check out this link for details http://www-1.ibm.com/support/docview.wss?uid=swg27006876).

If you just want to confirm the issue, or you need just a temporary fix, try this:

1) jar up all properties files for your project, (including default.properties in its full path), and put these into the WS common applications lib directory at the same level as the "profiles" directory.
2) Run the application - everything should work

This solution is strictly temporary, as all struts2 apps in this instance of WAS would have to use the same properties files. A better solution:

1) add a servlet that initializes the Struts Dispatcher with the servlet context:

import org.apache.struts2.dispatcher.Dispatcher;
 
public class LaunchServlet extends HttpServlet implements Servlet {
 
	public LaunchServlet() {
		super();
	}
 
	public void init(ServletConfig arg0) throws ServletException {
		
		// this works around a bug in the websphere classloader.
		super.init(arg0);
		Dispatcher d = new Dispatcher(getServletContext(), new HashMap<String, String>());	
		
	}
 
}

2) launch it at start-up (web.xml):

    <servlet>
      <servlet-name>dummyaction</servlet-name>
      <servlet-class>com.xxx.yyyyyy.service.LaunchServlet</servlet-class>
      <load-on-startup>1</load-on-startup>
    </servlet>

3) Run application and everything should work.