Apachi POI - Cell setCellValue thows NullPointerException

Question

When I am trying to update existing excel file I am encountering following error:

Exception in thread \"main\" java.lang.NullPointerException
    at xltest.main(         


        

Answer 1

The cell does not exist yet, so getCell returns null.

You must detect this and create the cell if it doesn't exist, with the createCell method:

if (cell == null)
{
    cell = sheet.getRow(0).createCell(3);
}
// Then set the value.
cell.setCellValue("onu");

Alternatively, there is an overload of getCell where you can specify a MissingCellPolicy so that a blank Cell is automatically created if it didn't already exist:

cell = sheet.getRow(0).getCell(3, Row.MissingCellPolicy.CREATE_NULL_AS_BLANK);