This week's book giveaway is in the OCAJP forum. We're giving away four copies of Programmer's Guide to Java SE 8 Oracle Certified Associate (OCA) and have Khalid A Mughal & Rolf W Rasmussen on-line! See this thread for details.
To test a web application, you can use JWebUnit or Selenium. The former is pure Java code to write tests, but doesn't execute in a real browser. There are a few ways to write Selenium tests - one is Java - and it does run in a real browser