It's interesting to see this written in Java, since the Excel application can be reached as a .NET object[0]. On top of that, Compare-Object is a built-in function for Powershell. Sure, with this built in Java you can use it to diff Excel spreadsheets on CentOS, but how often do you have those there? But in .NET most of the pieces are probably already there, so less work may have been needed to produce the same tool.

[0] http://www.madwithpowershell.com/2013/11/using-excel-functio...