The POI project consists of APIs for manipulating various file formats based upon Microsoft's OLE 2 Compound Document format using pure Java. A common misconception is that POI writes Excel files. POI is the name of the project. POI contains several components, one of which, HSSF, writes Excel files. The following are components of the entire POI project.POIFS is the oldest and most stable part of the project. It is our port of the OLE 2 Compound Document Format to pure Java. It supports both read and write functionality. All of our components ultimately rely on it by definition. HSSF is our port of the Microsoft Excel 97(-2002) file format (BIFF8) to pure Java. It supports read and write capability. HDF is our port of the Microsoft Word 97 file format to pure Java. It supports read and write capability. This component is in the early stages of design. Jump in! just do it Why not? Apache Software Foundation This software is released under the Apache Public License 1.1. For detailed legal and licensing issues, please read the LICENSE.* files in the /legal directory. This software includes software developed by the Krysalis Project (http://www.krysalis.org/). org.apache.poi