What is the correct way to deal with JSF 2.0 exceptions for AJAXified components?

You need to implement a custom ExceptionHandler for this which does basically the following when an exception occurs in an ajax request:

String errorPageLocation = "/WEB-INF/errorpages/500.xhtml";
context.setViewRoot(context.getApplication().getViewHandler().createView(context, errorPageLocation));
context.getPartialViewContext().setRenderAll(true);
context.renderResponse();

This is not exactly trivial if you want to take web.xml error pages into account. You'd need to parse the entire web.xml for this to find the error page locations. Also, when the exception occurred during render response, then you'd basically need to rebuild the whole view yourself. The OmniFaces component library has exactly such an exception handler, the FullAjaxExceptionHandler. You can find the full source code here and the showcase example here.

See also:

• using ExternalContext.dispatch in JSF error handler causes corrupt page rendering
• Session timeout and ViewExpiredException handling on JSF/PrimeFaces ajax request