title: What's causing this NPE when I request an action?
body: <p>This error was not there when I first run my program,then I tried some experiment to get the flow of MVC architecture but now it is showing me this exception.</p>
  
  <p>I guess the problem is when I request via subscribe button it will go to <code>struts.xml</code> where it will look for action. The problem is in package tag what should be there </p>
  
  <pre><code>java.lang.NullPointerException
      org.apache.struts2.impl.StrutsActionProxy.getErrorMessage(StrutsActionProxy.java:69)
      com.opensymphony.xwork2.DefaultActionProxy.prepare(DefaultActionProxy.java:185)
      org.apache.struts2.impl.StrutsActionProxy.prepare(StrutsActionProxy.java:63)
      org.apache.struts2.impl.StrutsActionProxyFactory.createActionProxy(StrutsActionProxyFactory.java:39)
      com.opensymphony.xwork2.DefaultActionProxyFactory.createActionProxy(DefaultActionProxyFactory.java:58)
      org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:501)
      org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:432)
      org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
      org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
      org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
      org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
      org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
      org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
      org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
      org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
      java.lang.Thread.run(Thread.java:619)
  </code></pre>
  
  <p><strong><code>struts.xml</code>:</strong></p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration                             2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"&gt;
  
  &lt;struts&gt;
      &lt;constant name="struts.devMode" value="true" /&gt;
      /*This package*/ 
      &lt;package name="Struts2Ex2" extends="struts.default"&gt;
          &lt;action name="test"
              class="MyPack.Verify"
              method="execute"&gt;
              &lt;result name="success"&gt;/Test2/WelcomeHome.jsp&lt;/result&gt;
          &lt;/action&gt;
      &lt;/package&gt;
   &lt;/struts&gt;
  </code></pre>