cell.setCellValue(listOfResults.get(iterationNumber));

0
1
1,23
213,23899

CellStyle style = wb.createCellStyle();
style.setDataFormat(HSSFDataFormat.getBuiltinFormat("0,00"));
cell.setCellStyle(style);
cell.setCellValue(Float.parseFloat(listOfResults.get(iteration)));
//after this I have a negative output with the following Exception
java.lang.NumberFormatException: For input string: "2,26776"

HSSFDataFormat.getBuiltinFormat("0,00")

cell.setCellValue(Float.parseFloat(listOfResults.get(iteration)))