Open XML Portfolio Manager
An open-source demo application on Codeplex shows how a Java application can generate Open XML spreadsheets to track a stock portfolio, including creation of graphs from a web application. The first release of the code was just uploaded a few days ago by my colleague Amir Shevat, a Microsoft Israel developer evangelist, so you can be among the first to download it. The setup instructions tell how to build and install the application on Apache Tomcat 5.5 and BEA WebLogic Server 9.2.
Most people keep track of stocks and similar information in a spreadsheet, and this application will generate XLSX spreadsheet files on the fly from the portfolio you set up, using a web service to retrieve the latest stock prices. Microsoft stock has been more variable in the last month than at any time since I started at the company, so this type of application is a little more interesting to me than it would have been last year. :-)
You can create your portfolio by entering the stocks into a template spreadsheet (provided), or you can use the web interface to create your portfolio:
After the portfolio is set up, you can generate a graph of any stock price, as an Open XML spreadsheet in an XLSX file:
The application, including source code, binaries, and setup instructions, is available here.