JSF2 with GAE and ViewScoped ManagedBean

Question

I managed to get a prototype with JSF2 get working at Googles AppEngine following this tutorial. Now I have some odd behavior with a ViewScoped ManagedBean:

@ManagedBean @ViewScoped
public class TestBean implements Serializable
{
  private String text;         //getter/setter
  private List<String> texts;    //getter

  @PostConstruct public void init() 
  {
    texts = new ArrayList<String>();
    texts.add("Test");
    text = new String();
  }

  public void save(ActionEvent ae)
  {  
    texts.add(text);
    text = new String();
  }
}

This is my .xhtml page:

<h:body id="body">
  <f:view contentType="text/html">
     <h:form id="frm">
        <p:panel>  
            <h:panelGrid columns="2" id="grid">   
                <p:inputText value="#{testBean.text}"/>  
                <p:commandButton value="Add" update=":frm:op @parent"
                                actionListener="#{testBean.save}" />   
            </h:panelGrid>
        </p:panel>
        <p:outputPanel id="op">
           <p:dataTable var="v" value="#{testBean.texts}">  
              <p:column><h:outputText value="#{v}" /></p:column>
           </p:dataTable>
        </p:outputPanel>
     </h:form>
  </f:view>
</h:body>

This works fine with a local deployment (Using the Eclipse tools for GAE), but if I deploy this to GAE, nothing happens if I click on the Add-Button. Additional Tests with the scope (at GAE) show the following after clicking on Add:

• @RequestScoped: Entered Text does not disappear, not added to dataTable
• @ViewScoped: Entered Text does not disappear, not added to dataTable
• @SessionScoped: Entered Text disappear, dataTable always has two entries: "Test" and the last entered Text

I have the same setting from the tutorial

<context-param>  //web.xml
  <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
  <param-value>server</param-value>
</context-param>

//appengine-web.xml
<sessions-enabled>true</sessions-enabled>

Update 1

Here are the results of additional tests with @ManagedBean @ViewScoped annotation:

During the first request (or manual refreh of the page), the @PostConstruct init() method is called. If I click on the button nothing happes, the request to test.jsf is logged in app engines log, but there is no log in my save() method. Firebug shows me a POST request to test.jsf and the following answer:

<?xml version='1.0' encoding='UTF-8'?>
<partial-response><error>
  <error-name>class javax.faces.application.ViewExpiredException</error-name>
  <error-message>
     <![CDATA[viewId:/test.jsf - View /test.jsf could not be restored.]]>
  </error-message>
  </error>
  <extension primefacesCallbackParam="validationFailed">
    {"validationFailed":false}
  </extension>
</partial-response>

Update 2

I have used mojarra-2.0.4 but now updated to 2.0.6. The same issue, but a new observation: If I clear all Firefox caches, the ViewExpiredException did not appear, but I'm only able to add 1 Element to the List<String>. The @PostConstruct is only invoked once and not for each click on the button.

Then I tried myfaces-2.0.7, but got this exception:

Uncaught exception from servlet
java.lang.NoClassDefFoundError: Could not initialize class
com.google.apphosting.runtime.security.shared.stub.javax.naming.InitialContext

I'm not sure if I should try to get myfaces working since google explicitly mentions mojarra (2.0.4) in their tutorial.

References

• ViewExpiredException on GAE
• JIRA JAVASERVERFACES-1886

Answer 1

Normally I don't answer my questions and I only rate this answer as a workaround and not as the correct answer. Event if I don't like client state saving, this seems to fix the odd behavior. But I have to check this in detail:

<context-param>
  <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
  <param-value>client</param-value>
</context-param>

Perhaps we should wait until JAVASERVERFACES-1886 is resolved.