So there seems to be a little bit of confusion. The code you posted is not Apache POI. And it isn't JXL (JXL @ sourceforge). I assumed (incorrectly) that it was JExcel (JExcel @ TeamDev) but was wrong. You must be using JExcelAPI (JExcelApi @ sourceforge). The problem with that is it does not support the XLSX format - only the older XLS format.
JExcel and Apache POI both support XLSX format.
Joined: Nov 24, 2012
sorry for the confusion Steve .
and yes it doesn't support for the xlxs format, but its working fine for xls format.