Well ... before getting overly excited about JIT one needs some information about where the bottlenecks in OpenACS 4.5 lie. Thus far, bottlenecks that have been uncovered lie in the realm of the RDBMS.
An apparent 10-20x win (which is easy to believe since JIT code, though typically dumb compiled code is at least compiled) sounds fantastic, but of course if you're speeding up something that accounts for just a couple of percent of the time involved in building dynamic pages then you've won essentially nothing.
So ... as usual my concern with enthusiasm for ns_java is the same concern I have with enthusiasm for adding Python pieces or more Perl peices. We really want to avoid a situtation where a newcomer needs to be fluent in Java, Tcl, Perl, Python and SQL in order to use our toolkit.
