If a a failure occurs during an interaction with a portlet, Simple Portal will throw a servlet exception with a message set to one of the category names as specified in Table 3.1, “Error Categories”

The default error handling strategy is handled by a servlet filter that catches error messages and translates them into HTTP errors. This filter is called <className>ErrorHandlingFilter</className> and is declared in the web.xml file of Simple Portal WAR file. This allows developers to change the error handling behavior if desired.

<web-app>
   ...
   <filter-mapping>
      <filter-name>ErrorHandlingFilter</filter-name>
      <url-pattern>*.jsp</url-pattern>
   </filter-mapping>
   ...
</web-app>