programming panda

GAE(Google App Engine) is a very high security environment, which google limits you in everything. In order to setup your struts 2 on GAE properly, you will need to change the OgnlRuntime security manager.

This is the error you will get on browser

HTTP ERROR: 404

result 'null' not found
RequestURI=/

And on your log

Jul 20, 2009 3:37:20 AM com.opensymphony.xwork2.util.logging.commons.CommonsLogger error
SEVERE: Unable to set parameter [location] in result of type [org.apache.struts2.dispatcher.ServletDispatcherResult]
Caught OgnlException while setting property 'location' on type 'org.apache.struts2.dispatcher.ServletDispatcherResult'. - Class: ognl.OgnlRuntime
File: OgnlRuntime.java
Method: invokeMethod
Line: 508 - ognl/OgnlRuntime.java:508:-1
 at com.opensymphony.xwork2.ognl.OgnlUtil.internalSetProperty(OgnlUtil.java:392)
 at com.opensymphony.xwork2.ognl.OgnlUtil.setProperty(OgnlUtil.java:143)
 at com.opensymphony.xwork2.ognl.OgnlReflectionProvider.setProperty(OgnlReflectionProvider.java:91)
...
...

What you have to do to fix this problem is to add a listener to set the security manager to null.

Listener:

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import ognl.OgnlRuntime;

public class ONGLFixListener  implements ServletContextListener, HttpSessionListener, HttpSessionAttributeListener {

   public ONGLFixListener()  {
   }

   public void contextInitialized(ServletContextEvent servletContextEvent)  {
       OgnlRuntime.setSecurityManager(null);
   }
  
   //Empty methods that do nothing for the interfaces

web.xml

  com.example.ONGLFixListener

This should fix the problem. =D