After launch and rendering single request to browser tomcat takes approximately 6 MB heap (as far as I can understand this is “common overhead”).
The rest is taken after subsequent requests made by the threads.
By default tomcat has 30 min session and unlimited active sessions count.
If I limit max sessions to 100 (or any CERTAIN positive value ) it does not run out of memory. hm-m-m-m… how many vaadin users have forgotten to limit active sessions count and may be a potential victim of such primitive attack? =) It seems this is worth mentioning in documentation and your book (I tried to search on this but found nothing).
Btw, I know that there are no production systems working with 32MB heap, that was just a test…
Anyway, thanks for your quick and responsive support.