7.12.5. Some common exceptions

If you are using JPA: 
<exception class="javax.persistence.EntityNotFoundException">
  <redirect view-id="/error.xhtml">
    <message>Not found</message>
  </redirect>
</exception>

<exception class="javax.persistence.OptimisticLockException">
  <end-conversation/>
  <redirect view-id="/error.xhtml">
    <message>
      Another user changed the same data, please try again
    </message>
  </redirect>
</exception>
If you are using the Seam Application Framework: 
<exception class="org.jboss.seam.framework.EntityNotFoundException">
  <redirect view-id="/error.xhtml"> 
    <message>Not found</message>
  </redirect> 
</exception>
If you are using Seam Security: 
<exception class="org.jboss.seam.security.AuthorizationException">
  <redirect>
    <message>You do not have permission to do this</message>
  </redirect>
</exception>

<exception class="org.jboss.seam.security.NotLoggedInException">
  <redirect view-id="/login.xhtml">
    <message>Please log in first</message>
  </redirect>
</exception>
And, for JSF: 
<exception class="javax.Faces.application.ViewExpiredException"> 
  <redirect view-id="/error.xhtml">
    <message>Your session has timed out, please try again</message> 
  </redirect> 
</exception>
A ViewExpiredException occurs when the user posts to a page after their session has expired. The conversation-required and no-conversation-view-id settings in the Seam page descriptor, discussed in Section 8.4, “Requiring a long-running conversation”, allow finer-grained control over session expiration while accessing a page used within a conversation.