Created attachment 23534 [details]
Test Spreadsheet

I encountered the following errors when I use "createSheet()" / "cloneSheet()" after "removeSheetAt()". The test spreadsheet is a .xlsx file which has two blank sheets.


Case 1
===============
    Workbook workbook = WorkbookFactory.create(new FileInputStream("Book1.xlsx"));
    workbook.removeSheetAt(0);
    workbook.createSheet();

 Error: java.lang.IllegalArgumentException: The workbook already contains a sheet of this name


Case 2 
===============
    Workbook workbook = WorkbookFactory.create(new FileInputStream("Book1.xlsx"));
    workbook.removeSheetAt(1);
    workbook.createSheet();

 Error: org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidOperationException: A part with the name '/xl/worksheets/sheet2.xml' already exists : Packages shall not contain equivalent part names and package implementers shall neither create nor recognize packages with equivalent part names. [M1.12]


Case 3
===============
    Workbook workbook = WorkbookFactory.create(new FileInputStream("Book1.xlsx"));
    workbook.removeSheetAt(0);
    workbook.cloneSheet(0);

 Error: org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidOperationException: A part with the name '/xl/worksheets/sheet2.xml' already exists : Packages shall not contain equivalent part names and package implementers shall neither create nor recognize packages with equivalent part names. [M1.12]


Case 4
===============
    XSSFWorkbook workbook = new XSSFWorkbook();
    workbook.createSheet();
    workbook.removeSheetAt(0);
    workbook.createSheet();

 Error: org.apache.poi.POIXMLException: org.apache.poi.openxml4j.exceptions.InvalidOperationException: A part with the name '/xl/worksheets/sheet1.xml' already exists : Packages shall not contain equivalent part names and package implementers shall neither create nor recognize packages with equivalent part names. [M1.12]