I am writing about Selenium, a portable automated testing framework which allows you to write tests in a number of languages C#, Perl, PHP, Ruby and most interestingly Java. The API it provides is just a flat bundle of methods which are quite easy to use.
Selenium IDE (provides environment for selenium tests) allows you to record, edit, debug and play tests within Firefox browser. This could also be used in a normal administrative work (not just the tests). Once you record the test you could export it as Java Test case which could be used in the automated tests. If you would like to see it in action then follow these steps.
If you want to see how to start with Selenium Web Driver then you can checkout a project from svn (../TeamJava/svn/muqeet/handsonselenium) . Once you download it you can run ‘mvn test’ (prerequisites are Maven, Firefox). The test tries to connect to kentor.se and changes the language to English with verification.
Having FireBug in Firefox or Developer debugger in IE(F12) helps a lot in writing Web driver tests.