title: ERROR: MAC did not verify! PrimeFaces
body: <p>I'm trying to update content in a JSF 2.0 webapp without refreshing the entire page.</p>
  
  <p>This is my xhtml</p>
  
  <pre><code>&lt;h:form id="form"&gt;  
      &lt;h:outputText id="txt_count" value="#{counterBean.count}" /&gt;  
  
      &lt;p:poll interval="3"   
              listener="#{counterBean.increment}" update="txt_count" /&gt;  
  &lt;/h:form&gt;  
  </code></pre>
  
  <p>And my bean</p>
  
  <pre><code>package org.primefaces.examples.view;  
  
  import java.io.Serializable;  
  
  import javax.faces.event.ActionEvent;  
  
  public class CounterBean implements Serializable{  
  
      private int count;  
  
      public int getCount() {  
          return count;  
      }  
  
      public void setCount(int count) {  
          this.count = count;  
      }  
  
      public void increment() {  
          count++;  
      }  
  }  
  </code></pre>
  
  <p>This compiles fine but when it runs I get the following error:</p>
  
  <p>ERROR: MAC did not verify!</p>