Because it's a RuntimeException I can't tell the user about the problem, e.g. file is too big. I can only show the user a standard error page :-(

What about a MaxRequestSizeException? If I have MaxRequestSizeException I can show the user a non-standard error page.

e.g.

<pages>
<exception class="org.jboss.seam.MaxRequestSizeException">
<redirect view-id="/uploadError.xhtml">
<message>File is too big</message>
</redirect>
</exception>
</pages>