I am new to portlet developmet. I was trying to develop and deploy simple portlet in Jboss portal 2.7.2 and Jboss AS 4.2.3/

Following is the code

Portlet extending GenericPortlet

package com.sampleportlet;

import java.io.IOException;

import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.GenericPortlet;
import javax.portlet.PortletConfig;
import javax.portlet.PortletException;
import javax.portlet.PortletRequestDispatcher;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.UnavailableException;



public class First extends GenericPortlet {

   
   
    public void init(PortletConfig portletConfig) throws UnavailableException,
            PortletException {
        super.init(portletConfig);
    }

    /**
     * Helper method to serve up the mandatory view mode.
     */
    protected void doHelp(RenderRequest request, RenderResponse response)
            throws PortletException, IOException {
        response.setContentType("text/html");
        PortletRequestDispatcher dispatcher = getPortletContext()
                .getRequestDispatcher("/WEB-INF/jsp/First_help.jsp");
        dispatcher.include(request, response);
    }

    /**
     * Helper method to serve up the mandatory view mode.
     */
    protected void doEdit(RenderRequest request, RenderResponse response)
            throws PortletException, IOException {
        response.setContentType("text/html");
        PortletRequestDispatcher dispatcher = getPortletContext()
                .getRequestDispatcher("/WEB-INF/jsp/First_edit.jsp");
        dispatcher.include(request, response);
    }

    /**
     * Helper method to serve up the mandatory view mode.
     */
    protected void doView(RenderRequest request, RenderResponse response)
            throws PortletException, IOException {
        response.setContentType("text/html");

        String name = (String) request.getParameter("name");

        if (name != null) {
            PortletRequestDispatcher reqDispatcher = getPortletContext()
                    .getRequestDispatcher("/WEB-INF/jsp/First_view.jsp");
            request.setAttribute("name", name);
            reqDispatcher.include(request, response);
        } else {
            PortletRequestDispatcher reqDispatcher = getPortletContext()
                    .getRequestDispatcher("/WEB-INF/jsp/First_edit.jsp");
            reqDispatcher.include(request, response);
        }
    }

    public void processAction(ActionRequest actionRequest,
            ActionResponse actionResponse) throws PortletException,
            IOException, UnavailableException {
        String name = (String) actionRequest.getParameter("name");

        // send name back to view
        actionResponse.setRenderParameter("name", name);
    }

}

WEB-INF/portlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<portlet-app xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd"
    version="2.0">
    <portlet>
        <portlet-name>FirstJspPortlet</portlet-name>
        <display-name>First Portlet</display-name>
        <portlet-class>com.sampleportlet.First</portlet-class>
        <supports>
            <mime-type>text/html</mime-type>
            <portlet-mode>VIEW</portlet-mode>
            <portlet-mode>EDIT</portlet-mode>
            <portlet-mode>HELP</portlet-mode>
        </supports>
        <portlet-info>
            <title>First Portlet</title>
        </portlet-info>
    </portlet>
   
</portlet-app>

WEB-INF/portlet-instances.xml

<?xml version="1.0" standalone="yes"?>
<deployments>
   <deployment>
         <instance>
            <instance-id>FirstPortletInstance</instance-id>
            <portlet-ref>FirstJspPortlet</portlet-ref>
         </instance>
   </deployment>
</deployments>

WEB-INF/firstjspportlet-object.xml

<?xml version="1.0" encoding="UTF-8"?>
<deployments>
    <deployment>
        <if-exists>overwrite</if-exists>
        <parent-ref>default.default</parent-ref>
        <window>
            <window-name>FirstPortletWindow</window-name>
            <content>
                <content-type>portlet</content-type>
                <content-uri>FirstPortletInstance</content-uri>
            </content>
            <region>center</region>
            <height>1</height>
        </window>
    </deployment>
</deployments>

WEB-INF/Jboss-portlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE portlet-app PUBLIC "-//JBoss Portal//DTD JBoss Portlet 2.6//EN"
        "http://www.jboss.org/portal/dtd/jboss-portlet_2_6.dtd">

<portlet-app>
   <remotable>true</remotable>
   <portlet>
      <portlet-name>FirstJspPortlet</portlet-name>
   </portlet>
</portlet-app>

Error I am getting is

2010-04-18 22:09:22,953 DEBUG [org.jboss.portal.portlet.container.com_sampleportlet_First] Loading portlet class com.sampleportlet.First
2010-04-18 22:09:22,958 DEBUG [org.jboss.portal.portlet.container.com_sampleportlet_First] Creating portlet object com.sampleportlet.First
2010-04-18 22:09:22,962 ERROR [org.jboss.portal.portlet.impl.container.LifeCycle] Cannot start object
org.jboss.portal.portlet.container.PortletInitializationException: The portlet FirstJspPortlet threw a runtime exception during init
    at org.jboss.portal.portlet.impl.jsr168.PortletContainerImpl.start(PortletContainerImpl.java:288)
    at org.jboss.portal.portlet.impl.container.PortletContainerLifeCycle.invokeStart(PortletContainerLifeCycle.java:76)
    at org.jboss.portal.portlet.impl.container.LifeCycle.managedStart(LifeCycle.java:92)
    at org.jboss.portal.portlet.impl.container.PortletApplicationLifeCycle.startDependents(PortletApplicationLifeCycle.java:351)
    at org.jboss.portal.portlet.impl.container.LifeCycle.managedStart(LifeCycle.java:128)
    at org.jboss.portal.portlet.deployment.jboss.PortletAppDeployment.start(PortletAppDeployment.java:226)
    at org.jboss.portal.core.deployment.jboss.PortletAppDeployment.start(PortletAppDeployment.java:94)
    at org.jboss.portal.server.deployment.jboss.DeploymentContext.start(DeploymentContext.java:99)
    at org.jboss.portal.server.deployment.jboss.PortalDeploymentInfoContext.start(PortalDeploymentInfoContext.java:220)
    at org.jboss.portal.server.deployment.jboss.ServerDeployer.start(ServerDeployer.java:217)
    at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819)
    at sun.reflect.GeneratedMethodAccessor212.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
    at $Proxy222.deploy(Unknown Source)
    at org.jboss.portal.server.deployment.jboss.ServerDeployer.deploy(ServerDeployer.java:259)
    at org.jboss.portal.server.deployment.WebAppAdapter.deploy(WebAppAdapter.java:53)
    at org.jboss.portal.server.deployment.WebAppIntercepter.handleNotification(WebAppIntercepter.java:159)
    at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.notification.NotificationListenerProxy.invoke(NotificationListenerProxy.java:153)
    at $Proxy224.handleNotification(Unknown Source)
    at org.jboss.mx.util.JBossNotificationBroadcasterSupport.handleNotification(JBossNotificationBroadcasterSupport.java:127)
    at org.jboss.mx.util.JBossNotificationBroadcasterSupport.sendNotification(JBossNotificationBroadcasterSupport.java:108)
    at org.jboss.deployment.SubDeployerSupport.emitNotification(SubDeployerSupport.java:340)
    at org.jboss.deployment.SubDeployerSupport.start(SubDeployerSupport.java:308)
    at org.jboss.web.AbstractWebContainer.start(AbstractWebContainer.java:482)
    at sun.reflect.GeneratedMethodAccessor105.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
    at org.jboss.mx.interceptor.DynamicInterceptor.invoke(DynamicInterceptor.java:97)
    at org.jboss.system.InterceptorServiceMBeanSupport.invokeNext(InterceptorServiceMBeanSupport.java:238)
    at org.jboss.wsf.container.jboss42.DeployerInterceptor.start(DeployerInterceptor.java:87)
    at org.jboss.deployment.SubDeployerInterceptorSupport$XMBeanInterceptor.start(SubDeployerInterceptorSupport.java:188)
    at org.jboss.deployment.SubDeployerInterceptor.invoke(SubDeployerInterceptor.java:95)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
    at $Proxy202.start(Unknown Source)
    at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782)
    at sun.reflect.GeneratedMethodAccessor26.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
    at $Proxy9.deploy(Unknown Source)
    at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymentScanner.java:421)
    at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentScanner.java:634)
    at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.doScan(AbstractDeploymentScanner.java:263)
    at org.jboss.deployment.scanner.AbstractDeploymentScanner.startService(AbstractDeploymentScanner.java:336)
    at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289)
    at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245)
    at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978)
    at $Proxy0.start(Unknown Source)
    at org.jboss.system.ServiceController.start(ServiceController.java:417)
    at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
    at $Proxy4.start(Unknown Source)
    at org.jboss.deployment.SARDeployer.start(SARDeployer.java:304)
    at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782)
    at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:766)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155)
    at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
    at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142)
    at org.jboss.mx.server.Invocation.invoke(Invocation.java:88)
    at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
    at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
    at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210)
    at $Proxy5.deploy(Unknown Source)
    at org.jboss.system.server.ServerImpl.doStart(ServerImpl.java:482)
    at org.jboss.system.server.ServerImpl.start(ServerImpl.java:362)
    at org.jboss.Main.boot(Main.java:200)
    at org.jboss.Main$1.run(Main.java:508)
    at java.lang.Thread.run(Thread.java:613)
Caused by: java.lang.ClassCastException: com.sampleportlet.First
    at org.jboss.portal.portlet.impl.jsr168.PortletContainerImpl.start(PortletContainerImpl.java:254)

Please let me know what needs to be changed.