This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Instead of writing a search engine from scratch in java, if it is possible you can use a third party search engine which is compatible with applications written in Java like Inktomi's Inktomi search software(formerly known as Ultraseek). This search engine comes with a Java API to enable integration with Java applications and extend search engine's capabilities. You can get more information from http://www.inktomi.com/products/search//products/ultraseek/index.html Hope this helps.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com