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The ExceptionHandler is used to clean Seam contexts and transactions after errors.
<context-param> <param-name>org.jboss.portletbridge.ExceptionHandler</param-name> <param-value> org.jboss.portletbridge.SeamExceptionHandlerImpl </param-value> </context-param>
There is workaround for Seam 2.0.0/2.0.1 distributions. This is not needed for Seam 2.1.x releases.
<context-param> <param-name>javax.faces.LIFECYCLE_ID</param-name> <param-value>SEAM_PORTLET</param-value> </context-param>