Getting Error Message : org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidFormatException: Package should contain a content type part [M1.13]

Reason :

 If we are using xls format excel file for reading/writing by using XSSF apachi poi then we will get this issue

Solution :

XSSF used only for XLSX excel file format only.
HSSF used only for XLS excel file format only










So we will use xls format excel file for reading/writing by using HSSF apachi poi for avoiding this issue.