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.
Look on the sourceForge there is a set of API's to generate PDF's... I am sure they can provide a least basic PDF viewing. There was also a post on a javaranch forum about the different PDF viewer. The post was made by Benjamin LEONARD (an dammed good java developper & more over a frien of mine). I remember he gave 2 package to do so !