Java.lang.ClassCastException in simple struts application. please help me!

Question

I have a simple struts application, it only have a login form. however, it's alway throw java.lang.ClassCastException when I submit the form. Here is full stack trace:
14-03-2007 17:04:50 org.apache.struts.chain.ComposableRequestProcessor init
INFO: Initializing composable request processor for module prefix ''
14-03-2007 17:04:50 org.apache.struts.chain.commands.servlet.CreateAction getAction
INFO: Initialize action of type: ndlinh.struts.lab.RegistrationForm
14-03-2007 17:04:50 org.apache.struts.chain.commands.AbstractExceptionHandler execute
WARNING: Unhandled exception
java.lang.ClassCastException: ndlinh.struts.lab.RegistrationForm
     at org.apache.struts.chain.commands.servlet.CreateAction.getAction(CreateAction.java:66)
     at org.apache.struts.chain.commands.AbstractCreateAction.execute(AbstractCreateAction.java:82)
     at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:48)
     at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
     at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
     at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
     at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:280)
     at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1858)
     at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:459)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
     at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
     at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
     at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
     at java.lang.Thread.run(Thread.java:595)
14-03-2007 17:04:50 org.apache.struts.chain.commands.ExceptionCatcher postprocess
WARNING: Exception from exceptionCommand 'servlet-exception'
java.lang.ClassCastException: ndlinh.struts.lab.RegistrationForm
     at org.apache.struts.chain.commands.servlet.CreateAction.getAction(CreateAction.java:66)
     at org.apache.struts.chain.commands.AbstractCreateAction.execute(AbstractCreateAction.java:82)
     at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:48)
     at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
     at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
     at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
     at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:280)
     at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1858)
     at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:459)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
     at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
     at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
     at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
     at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
     at java.lang.Thread.run(Thread.java:595)
Here is my code:
package ndlinh.struts.lab;
import javax.servlet.http.HttpServletRequest;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
public class RegistrationForm extends ActionForm {
     private String userid = null;
     private String password = null;
     private String password2 = null;
     public RegistrationForm() {
          System.out.println("************ Registration Form created *************");
      * @return the password
     public String getPassword() {
          return password;
      * @param password the password to set
     public void setPassword(String password) {
          this.password = password;       
      * @return the password2
     public String getPassword2() {
          return password2;
      * @param password2 the password2 to set
     public void setPassword2(String password2) {
          this.password2 = password2;
      * @return the userid
     public String getUserid() {
          return userid;
      * @param userid the userid to set
     public void setUserid(String userid) {
          this.userid = userid;
     public void reset(ActionMapping arg0, HttpServletRequest arg1) {
          userid = "";
          password = "";
          password2 = "";
package ndlinh.struts.lab;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
public final class RegistrationAction extends Action {
     public ActionForward execute(ActionMapping mapping, ActionForm actionForm,
                                         HttpServletRequest request, HttpServletResponse response)
          try {
               System.out.println("*******************" + actionForm.toString() + "*******************");
               RegistrationForm form = (RegistrationForm)actionForm;     
               String username = form.getUserid();
               String password = form.getPassword();
               System.out.println(username);
               // simple login checking.
               // if userid equals password, user can login to system
               if ( username.equalsIgnoreCase(password)) {
                    return mapping.findForward("success");
               } else {
                    return mapping.findForward("failure");
          } catch (Exception e) {
               e.printStackTrace();
               return mapping.findForward("failure");
}registration.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
     <html:form action="/register">
          Username: <html:text property="userid" /> <br />
          Password: <html:password property="password" /> <br />
          Re-type: <html:password property="password2" />
          <html:submit value="Register" />
     </html:form>
</body>
</html>struts-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
<struts-config>
  <form-beans>
       <form-bean name="registrationForm" type="ndlinh.struts.lab.RegistrationForm" />
  </form-beans>
  <action-mappings>
       <action path="/register"
               type="ndlinh.struts.lab.RegistrationForm"
               name="registrationForm"
               validate="false"
               scope="request"
               input="registration.jsp" >
            <forward name="success" path="/jsp/success.jsp"  />
            <forward name="failure" path="/jsp/failure.jsp"  />
       </action>
  </action-mappings>
</struts-config>web.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
  <servlet>
    <servlet-name>action</servlet-name>
    <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
    <init-param>
      <param-name>config</param-name>
      <param-value>/WEB-INF/struts-config.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>action</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>System information:
Tomcat 5.5.20
Struts 1.3.5
JDK1.5.08

Answer 1

struts-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
<struts-config>
  <form-beans>
       <form-bean name="registrationForm" type="ndlinh.struts.lab.RegistrationForm" />
  </form-beans>
  <action-mappings>
       <action path="/register"
               type="ndlinh.struts.lab.RegistrationAction" // action class
               name="registrationForm" // form bean name
               validate="false"
               scope="request"
               input="registration.jsp" >
            <forward name="success" path="/jsp/success.jsp"  />
            <forward name="failure" path="/jsp/failure.jsp"  />
       </action>
  </action-mappings>
</struts-config>HTH