This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
First, do you know any Java? Regardless of what you want to do with Java, you need to learn the fundamentals first. The best way to do this is with a good introductory book, like Head First Java. In the meantime, you might try The Java Tutorial online.
Second, what exactly do you want this web-based application to do? Do you know whether you want this to be an applet? Or are you thinking about Servlets/JSP?
"We're kind of on the level of crossword puzzle writers... And no one ever goes to them and gives them an award." ~Joe Strummer sscce.org