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getting error while loading action servlet for eg in the book Head First Servlet  RSS feed

 
rohit raj
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Posts: 6
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Hello,

I am getting the following error when I start tomcat with the code of BeerSelectForm, BeerSelectAction etc. Here is the error

2005-02-07 21:35:59 StandardContext[/BeerStruts]StandardWrapper.Throwable
java.lang.NullPointerException
at org.apache.struts.action.ActionServlet.parseModuleConfigFile(ActionServlet.java:1003)
at org.apache.struts.action.ActionServlet.initModuleConfig(ActionServlet.java:955)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:470)
at javax.servlet.GenericServlet.init(GenericServlet.java:256)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1044)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:887)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3959)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4284)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:866)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:850)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:638)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:320)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:875)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:727)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:477)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1008)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:394)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1134)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:832)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1126)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:521)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2345)
at org.apache.catalina.startup.Catalina.start(Catalina.java:594)
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:324)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:297)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:398)

2005-02-07 21:35:59 StandardContext[/BeerStruts]Servlet /BeerStruts threw load() exception
javax.servlet.ServletException: Servlet.init() for servlet FrontController threw exception
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1086)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:887)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3959)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4284)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:866)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:850)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:638)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:320)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:875)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:727)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:477)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1008)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:394)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1134)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:832)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1126)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:521)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2345)
at org.apache.catalina.startup.Catalina.start(Catalina.java:594)
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:324)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:297)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:398)
----- Root Cause -----
java.lang.NullPointerException
at org.apache.struts.action.ActionServlet.parseModuleConfigFile(ActionServlet.java:1003)
at org.apache.struts.action.ActionServlet.initModuleConfig(ActionServlet.java:955)
at org.apache.struts.action.ActionServlet.init(ActionServlet.java:470)
at javax.servlet.GenericServlet.init(GenericServlet.java:256)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1044)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:887)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3959)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4284)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:866)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:850)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:638)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:320)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:875)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:727)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:477)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1008)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:394)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:166)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1134)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:832)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1126)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:521)
at org.apache.catalina.core.StandardService.start(StandardService.java:519)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2345)
at org.apache.catalina.startup.Catalina.start(Catalina.java:594)
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:324)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:297)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:398)


Here is my struts config and web.xml

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE struts-config PUBLIC
"-//Apache software Foundation//DTD Struts Configuration 1.0//EN"
"http://jakarta.apache.org/struts/dtds/struts-config_1_0.dtd">

<struts-config>

<form-beans>
<form-bean name="selectBeerForm"
type="com.example.web.BeerSelectForm" />
</form-beans>

<action-mappings>

<action path="/SelectBeer"
type="com.example.web.BeerSelectAction"
name="selectBeerForm"
scope="request"
validate="true"
input="/form.jsp">

<forward name="show_results" path="/result.jsp" />

</action>

</action-mappings>


</struts-config>


<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>FrontController</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>FrontController</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>

I can not understand where is the action servlet failing to load on startup. I have made sure the three struts jar files are in lib directory.

Did anyone else get the same error ? I searched on google and javaranch but could not find exact match for the answer.

Thanks

Rohit Raj
 
Nathan Hook
Ranch Hand
Posts: 81
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this error right here gives away where the problem is...



The BeerStruts servlet is throwing an exception from either the init or load methods.

Best of Luck,

Nate
[ February 09, 2005: Message edited by: Nathan Hook ]
 
Srilakshmi Vara
Ranch Hand
Posts: 169
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Hi,

To initiate struts you need following things,

1. proper entry into web.xml to initialize struts
2. struts-config.xml with proper action tag
3. all struts tld files in web-inf folder
4. struts jar file should be in web-inf/lib folder

Programs:
1. JSP file
2. ActionForm
3. Action

All the Best!!
 
rohit raj
Greenhorn
Posts: 6
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Please ignore.. the file name of struts-config had a typo - Rohit Raj
 
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