title: Primefaces dataTable with checkbox not work
body: <p>I am using Primefaces 4.0 with jsf2.2.</p>
  
  <p>When I use dataTable with checkbox, it won't send back any record whenever I select records.</p>
  
  <p>It supposed to send back the record once I click the checkbox.</p>
  
  <p>I remove extra stuff and make my code simple to test it:</p>
  
  <p>There is a polling printing selected items every second, so that I can check is there something sent back. </p>
  
  <p>And after doing this, I found there's nothing sent back.
  Here's my code:</p>
  
  <p>Page:</p>
  
  <pre><code>&lt;h:head&gt;
      &lt;title&gt;System Monitor&lt;/title&gt;
  
  &lt;/h:head&gt;
  
  &lt;h:body&gt;
      &lt;h:form&gt;
          &lt;p:poll interval="1" listener="#{indexBean.printSelect()}"/&gt; 
      &lt;/h:form&gt; 
  
      &lt;h:form&gt;     
  
          &lt;p:dataTable id='data' var="proc" value="#{indexBean.procStatus}"
                       rowKey="#{proc.pid}" selection="#{indexBean.selectedProcs}"&gt;
              &lt;p:column&gt;
                  &lt;f:facet name='header'&gt;
                      &lt;h:outputText value='Process Name'/&gt;
                  &lt;/f:facet&gt;
                  &lt;h:outputText styleClass="outputCell" id="pname" value='#{proc.name}'/&gt;
              &lt;/p:column&gt;
              &lt;p:column selectionMode="multiple"/&gt;
          &lt;/p:dataTable&gt;
  
      &lt;/h:form&gt;
  &lt;/h:body&gt;
  </code></pre>
  
  <p>Backing Bean:</p>
  
  <pre><code>@ManagedBean(name = "indexBean")
  @ViewScoped
  public class indexBean implements Serializable {
  private ProcStatDataModel procStatus;
  private SingleProcess[] selectedProcs;
  
  @PostConstruct
  public void loadProcStat() {
      List&lt;SingleProcess&gt; temp = new ArrayList&lt;&gt;();
      temp.add(new SingleProcess("test1"));
      temp.add(new SingleProcess("test2"));
      temp.add(new SingleProcess("test3"));
      procStatus = new ProcStatDataModel(temp);
  }
  
  public void printSelect() {
      if (selectedProcs != null) {
          String str = "";
          for (SingleProcess sp : selectedProcs) {
              str += sp.getName() + "_";
          }
          System.out.print(str);
      } else {
          System.out.println("selectedProcs is null");
      }
  }
  
  public ProcStatDataModel getProcStatus() {
      return procStatus;
  }
  
  public SingleProcess[] getSelectedProcs() {
      return selectedProcs;
  }
  
  public void setSelectedProcs(SingleProcess[] selectedProcs) {
      this.selectedProcs = selectedProcs;
  }
  }
  </code></pre>
  
  <p>I've tried attaching <code>rowCheckListener</code> like <a href="https://stackoverflow.com/questions/12650546/checkbox-datatable-primefaces-doesnt-working">this</a> before but in vain.</p>
  
  <p>Also, I tried adding <code>f:view contentType="text/html"</code> like <a href="https://stackoverflow.com/questions/5569502/primefaces-datatable-selectionmode-multiple-not-working-with-mojarra">this</a> and it was not help.</p>
  
  <p>It's weird because I do the same thing with the case of <a href="http://www.primefaces.org/showcase/ui/datatableRowSelectionRadioCheckbox.jsf" rel="nofollow noreferrer">primefaces show case</a> and it acts as I think. So I think this approach is OK, there should be something wrong in my code.</p>
  
  <p>Any help is appreciated. Thanks in advance.</p>