Apache POI is a free and open source java library used for reading and writing Microsoft document formats. Apache POI is purely written in java language for creating Microsoft Office file formats such as Excel, Power point, Visio, MS Word etc. The name POI was originally an acronym for Poor Obfuscation Implementation, referring humorously to the fact that the file formats seemed to be deliberately obfuscated, but poorly, since they were successfully reverse-engineered.

Step 1 - Download POI jar file from http://poi.apache.org/download.php.
Step 2 - Add POI jar into classpath by rightclick on project >> properties >> java buildpath >> add external jars >> browse for POI jar >> click OK.

Step-3 Create java class by right-click on project >> New >> class >> class name >> finish.