Website testing and accessibility have been interests of mine for a while and over the last couple of months I have been supporting the web accessibility testing project: I helped develop a core rule set of automate-able accessibility issues based on the WCAG standards and Open-Ajax in Java.
One of the key criteria for the library was for it to be used in a number of different environments like WebDriver based automated tests to inspect dynamic page content or static analysis of crawled pages running inside a map reduce job.
If you're interested in getting involved or using the library please contact us via the project page.