The page describing the open sesson in view pattern has this caveat:
Quote:
Since the Session is flushed after the view has been rendered, database exceptions might occur after a successful output has been generated. If you use plain JSP and servlets the page output will be rendered into a buffer, usually 8K. If the buffer is full, it is flushed to the client browser! So, your user might see a successful page (200 OK) but in fact an exception occurred. To avoid this, don't render into the servlet engine buffer or increase the buffer size to a safe value. Most web frameworks avoid this issue by not rendering into the standard servlet engine buffer, but into their own.
http://www.hibernate.org/43.html