What happens for exceptions in JPM transition actions?

[nstoddar]

The title pretty much says it all --- what happens when an action triggered by a page transition throws an exception? Will it simply bubble-up to get handled somewhere, or can that be configured as part of the pageflow, or will the current page be displayed again?

I'm thinking about the example in the documentation:

<page name="displayGuess" view-id="/numberGuess.jsp">
 <redirect/>
 <transition name="guess" to="evaluateGuess">
 <action expression="#{numberGuess.guess}" />
 </transition>
</page>

[nstoddar]

You can ignore this. I hit the submit button too soon, and just afterwords saw the "exception-handler" element. Can somebody shed any light on what the "script" element is used for? I'm assuming that the "action" expression gets evaluated and a transition takes place based on the return value. "exception-class" is obvious, but the "script" one is puzzling.