[SOLVED] delete all empty rows in excel file with JAVA

can someone tell me how to iterate and delete all the empty rows in excel file using apache poi? I am calling those 2 functions with row indexes that i wish to delete, but the second one (shift) is always giving me Minumum row index is 0 exceltion.

 public static void removeRow(HSSFSheet sheet, int rowIndex) {

   HSSFRow removingRow = sheet.getRow(rowIndex);
   if (removingRow != null) {
       sheet.removeRow(removingRow);
   }
 }

 public static void shiftRow(HSSFSheet sheet, int rowIndex) {
   int lastRowNum = sheet.getLastRowNum();
   if (rowIndex >= 0 && rowIndex < lastRowNum) {
       sheet.shiftRows(rowIndex+1, rowIndex+1, -1);
   }
 }

Thanks