“Package should contain a content type part [M1.13]”

Question

I am attempting to write to an Excel file however I keep getting the error:

Exception in thread \"main\" org.apache.poi.POIXMLException: org.apache.po

Answer 1

Another possible solution is

Workbook workbook = WorkbookFactory.create(source)

WorkbookFactory should be provided by Apache POI you are using (if not upgrade to newer version). It recognize file format and creates concrete implementation of Workbook interface (XSSFWorkbook or HSSFWorkbook). The source parameter can be java.io.InputStream or java.io.File.