Reading and Writing Microsoft Excel .xls files in Java

JExcel API:
http://jexcelapi.sourceforge.net/

Tutorial:
http://www.andykhan.com/jexcelapi/tutorial.html

Download:
http://sourceforge.net/projects/jexcelapi/files/jexcelapi/2.6.12/

Java XML Parsing Goodness :)

http://www.javaprogrammingforums.com/file-input-output-tutorials/32-how-read-xml-document-java-dom-parse.html

Java Regular Expressions

Regular Expressions In Java:
http://docs.oracle.com/javase/tutorial/essential/regex/
http://www.vogella.com/articles/JavaRegularExpressions/article.html

Another Good Regular Expressions:
http://www.tutorialspoint.com/java/java_regular_expressions.htm

Java XML Encoding And Decoding

Encoding:
http://docs.oracle.com/javase/6/docs/api/java/beans/XMLEncoder.html

Decoding:
http://docs.oracle.com/javase/7/docs/api/java/beans/XMLDecoder.html