Exceptions that occur in an Action class can be catched in the Action class or handled by registered handlers, in the struts-config.xml file, that route control to specified error pages.

Ted Husted

It depends on when the error occurs. When you are using Tiles, the response is rendered tile-by-tile. Once the response starts to render, control cannot be forwarded to another page. So with Tiles, you may also see an error message for one tile, while the others render just fine.

But, if you do not have any business/system logic in your tiles, this type of error should not happen in production. You should be able to detect any runtime problems in your Action and forward to an error page yourself, without relying on the container's assistance.

HTH, Ted

Ted Husted,
Struts in Action