I need to create user account registration / login / management components for a Spring backed web application. I'm intending to use Acegi to help with the authentication side of things. Is there a framework / set of components that can help with the boilerplate account validation e-mails, forgotten password handling etc functions?
Related but not the same as this question, and almost exactly the same as a question on the SpringSource forum, that was asked several years ago.
Take a look at the Emmet project. Providing a user management subsystem for Spring-based projects is one of its two aims. (The other aim is to provide SpringSecurity enhancements and potted wiring files to support Shibboleth, various kinds of "hybrid" login schemes, and other things.)
(Disclaimer - I'm the primary author of Emmet.)
Beyond Emmet, there really doesn't seem to be a good solution here. Part of the problem is the lack of consensus and standards, as observed by the University of Cambridge security researchers: -
Password implementation is a very common task implemented by thousands of websites, but standards are doing little to improve the process. Until good standards become available, their role is partially fulfilled by industry de-facto standards or community-driven guidelines which remain scattered on the Web amidst much noise.
Passwords in the wild, part III: password standards for the Web
(The rest of that blog series is very interesting and useful in this area).
Some of the functionality is provided by Spring Security (e.g. Password encoding components).