CommandLinks and CommandButtons in Datatable do not work

Question

I have read the threads about this issue and am aware of the fact that there is a problem, if the backing bean is in request scope. However, my backing bean is in session scope and it still does not work - my action methods are never called. What's more, I have another backing bean in session scope, where it works perfectly and I cannot see any difference between them.
Here's the code, my backing bean is dms:
<h:form rendered="#{dms.documents.rowCount > 0}">
<h:dataTable rowClasses="..." headerClass="..." value="#{dms.documents}"
columnClasses="..." var="item" border="1" cellpadding="2" cellspacing="0">
<h:column>
<f:facet name="header">
<h:outputText>DocName</h:outputText>
</f:facet>
<h:commandLink action="#{dms.test}" value="#{item.docName}"/>
</h:column>
<h:column>
<f:facet name="header"/>
<h:commandButton id="foo" value="View" action="#{dms.test}"/>
</h:column>
</h:dataTable>
<h:commandLink action="#{dms.test}" value="Clickme"/>
</h:form>
Here is the code in the backing bean:
public String test() {
System.out.println("Hooray");
return "mainPage";
And this in faces-config.xml:
<managed-bean>
<managed-bean-name>dms</managed-bean-name>
<managed-bean-class>com.mypackage.DmsController</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
Only the last link, the one outside the datatable and titled "Clickme", works. I can see "Hooray" in the logfile and am redirected to the main page. If I click any of the links or buttons in the datatable, nothing is written to the log and the same page is loaded again, but only the static content is displayed, i.e. no JSF tags are evaluated, they are just dropped. There are, however, a few hidden input fields called javax.faces.ViewState, which I don't know where they are coming from.
As I said, I have another backing bean in session scope, which is modelled exactly like that and it works there. Maybe JSF apps are supposed to have only one controller?
Many thanks in advance for any pointers,
Ulrich
Edit: It doesn't change anything if I put the backing bean in application scope. I did have the same problem before with my other backing bean, but could solve it there by putting it from request scope to session scope.

Answer 1

<h:dataTable value="#{dms.documents}">How do you load this list? This list should not be null during the INVOKE_APPLICATION phase.
Try stubbing the List right in the getDocuments() method and see if it works.