Weblets are Java programs that run in a browser, using DirectDOM to directly manipulate displayed documents. Like most Web-based programs, weblets pose a threat to system security if they're mishandled. Fortunately, weblets come with built-in security in the form of the Java sandbox. This final installment of a three-part series on DirectDOM and weblet-based development shows you how to use the sandbox to your best advantage. With simple, working examples, this article demonstrates what a weblet can and can't do by default, and also shows you how to get around the constraints of the sandbox when the situation calls for it.