I am developing a typical web application to serve data from a RDB as HTML
to browser clients. So far I have used lightweight servlets and custom classes
to perform all the required processing, but I am running into issues such
as security, transactions etc that seem to have been addressed by EJB.

My question is this: should I switch to EJB (which I have yet to learn) or
are these components too 'heavyweight' and slow for a lightweight application
like mine where performance is a critical concern?

I would appreciate a cc: to the email above,

Many Thanks,
Ewan