I had an odd case where I use the OpenSessionInView
pattern to keep the database session open until the view (the
JSP) had completely rendered.
I had an entire ViewHelper layer which would handle mundane tasks such as populating DisplayTag tables and Struts HTML tag library <html

ptionsCollection> tags.
One day, one of my JSPs would not render, claiming an issue with an expression language (EL) definition. I knew something was up, but did not have a full stacktrace to solve the problem. I spent an entire afternoon trying to figure it out.
The next morning I created an Advice class that implemented ThrowsAdvice on the ViewHelper class. All that was in the method was a simple e.printStackTrace().
Within 5 minutes, I found the problem was a ClassCastException, and within 10 the problem was solved.
There are definitely arguments against using Open Session In View (and this was probably one of them). However, rewriting the entire user interface was not an option.
Jason