Java & Excel Documents
During my internship, I was asked to code an application that parses a given text and adds the data to an Excel document. Parsing was easy, but Excel part seemed difficult. But after a quick google search, I found JExcelApi. It is simple, and nicely documented. Thanks to JExcelApi coders, I finished the application in just a few hours.
These kind of situations makes any coder appreciate "free software".