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.
You can use Java and XML Binding APIs like JAXB APIS.
As you have the XSD file you can run XJC compiler and generate the Java Objects corresponding to your XML Schema.
Once done un-marshal the XML file to populate Java Tree structure from the XML input.
You can also use Castor APIs which is similar to JAXB.