Issue while upgrading to struts version 2.5.17

Question

I am trying to upgrade struts version from 2.3.35 to 2.5.17 but I encountered an issue as below:

java.lang.NullPointerException
    at com.opensymphony.xwork2.util.fs.StrutsJarURLConnection.getInputStream(StrutsJarURLConnection.java:170)
    at com.opensymphony.xwork2.util.fs.JarEntryRevision.needsReloading(JarEntryRevision.java:84)
    at com.opensymphony.xwork2.util.fs.DefaultFileManager.fileNeedsReloading(DefaultFileManager.java:65)
    at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.needsReload(XmlConfigurationProvider.java:428)
    at org.apache.struts2.config.StrutsXmlConfigurationProvider.needsReload(StrutsXmlConfigurationProvider.java:163)

I have been using this guide to migrate to struts version 2.5.17: https://cwiki.apache.org/confluence/display/WW/Struts+2.3+to+2.5+migration

I suspect it to be issue with tiles.

I have upgraded all struts related jar to version 2.5.17 including struts2-tiles-plugin. I have also upgraded all tiles related jars to 3.0.7.

Also I have removed the Xwork-core jar as from 2.5 xwork being merged to struts2-core jar.

Am I doing anything wrong.

Please note: I have not done any code changes as of now. The code works perfectly with struts version 2.3.35. But as soon as I have upgraded the struts version along with tiles version I started getting this issue.

Can some one please suggest If I am doing anything wrong?

Answer 1

Yes, there are supposed to be errors without code changes.

I don't think you are doing something wrong.

After adding the new .jars and removing the old ones it will only work when the code is compliant with the new framework.

---

Code changes would be:

.xml

1. Add the following <code> to web.xml.

<filter>
<filter-name>struts2</filter-name>
<filter-class> org.apache.struts2.dispatcher.FilterDispatcher
</filter-class>
</filter>

<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
</web-app>

2. Change struts-config.xml to struts.xml and make following changes:

   You can remove struts-config.xml completely and use annotations instead of .xml file.( since struts 2.5.17 )

<?xml version="1.0" encoding="ISO-8859-1" ?>        <!-- change to UTF-8 -->
<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.3//EN"
"http://struts.apache.org/dtds/struts-config_1_3.dtd "> <!-- change to struts-2.5.dtd -->
<struts-config>                     <!-- change to <struts>  -->
<!-- add <include file="struts-default.xml"/> -->
<form-beans>
<form-bean name="MyClassForm" type="forms.MyClassForm">
</form-bean>
</form-beans>

<action-mappings>       <!-- change to <package name="hello-default" extends="struts-default"> -->
<action path="/MyClass" name="MyClassForm" type="actions.MyClassAction"
validate="false">
<action name = “MyClass” class = “actions.MyClass”>
<forward name="success" path="/Index.jsp"/>
<result> /Index.jsp </result>
</action>
</action>
</action-mappings>          <!-- change to  </package> -->
<message-resources parameter="resources"/>
</struts-config>                <!-- change to  </struts> -->

---

.java

3. Remove ActionForm.java files.

   Properties are included in ActionSupport class which our Action class is supposed to extend.

4. Change Action.java

import javax.servlet.http.*;
import org.apache.struts.action.*;

public class MyClassAction extends Action // change to ActionSupport {  
//fields are now a property of the ActionSupport class  

public ActionForward execute(
ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception {

// change to public String execute() throws Exception {

MyClassForm input = (MyClassForm) form; // don't need this
input.setField1(“Hello”);    // change to setMessage(“Hello”);
return mapping.findForward(“success”);    // change to return Action.SUCCESS;

---

.jsp

5. Actions to be performed in this JSP are:

   • Replace <%@ taglib %> directive
   • Use new set of tags defined by the struts-tags.tld

    <%@ taglib prefix="s" uri="/struts-tags" %>
    <html>
    <head>
    <title>Hello!</title>
    </head>
    <s:form action="submit.action" method="post">
    <body>
    <s:textfield label="Name" name=" field1" />
    <s:property value="field1"/>
    <s:submit" />
    </body>
    </s:form>
    </html>

Cheers.

Answer 2

I got this resolved by upgrading struts version to 2.5.18. It also worked fine when I downgraded the struts version to 2.5.13.

But it is not recommended to use struts version between 2.5.16 and 2.3.36 (inclusive), so I have upgraded it to 2.5.18