rollno  user_name   user_email_id   class_type  request_status
--------------------------------------------------------------
CM5C9CBJJP  Isaac James isaac.james@gmail.com   1   Accepted
E6U13NFHGG  Sean Allan  sean.allan@gmail.com    1   Deactivated
SNAJHHVV8Q  Dylan Avery dylan.avery@gmail.com   1   Accepted
RNN71FJ5QS  Max Fisher  max.fisher@gmail.com    1   Rejected
6NKKI603BM  Owen Grant  owen.grant@gmail.com    1   Deactivated

public class StoreStudents {

        public static void main(String[] args) throws IOException {
            //HashMap Declaration.
            HashMap<String, List<String>> map = new HashMap<>();
            List<String> studentData = new ArrayList<>();
            // Read Excel FIle Sheet
            File excelFile = new File("user_details.xlsx");
            FileInputStream fis = new FileInputStream(excelFile);
            XSSFWorkbook workbook = new XSSFWorkbook(fis);
            XSSFSheet sheet = workbook.getSheetAt(0);
            Iterator<Row> rowIt = sheet.iterator();
            String k1 = "default";
            int count = 0,objCount = 0;
            while(rowIt.hasNext()) {
              count = count + 1;
              Row row = rowIt.next();
              // iterate on cells for the current row
              Iterator<Cell> cellIterator = row.cellIterator();
              if (row.getRowNum() != 0) {
                  while (cellIterator.hasNext()) {
                    Cell cell = cellIterator.next();
                    //System.out.println(cell.getColumnIndex());
                    if (cell.getColumnIndex() == 0) {
                        k1 = cell.toString();
                        System.out.println("1. key is " + k1);
                    }
                    else {
                    studentData.add(cell.toString());
                    //System.out.println(studentData);
                    //System.out.print(cell.toString() + ";");
                    }
                  }
              }
              System.out.println("key is " + k1);
              map.put(k1, studentData);
              System.out.println(map);
              studentData.clear();
              System.out.println(map);
              objCount = objCount + 1;
            }

        }

    }

Output:
key is default
{default=[]}
1. key is CM5C9CBJJP


key is CM5C9CBJJP
{CM5C9CBJJP=[Isaac James, isaac.james@gmail.com, 1.0, Accepted], default=[Isaac James, isaac.james@gmail.com, 1.0, Accepted]}
1. key is E6U13NFHGG


key is E6U13NFHGG
{CM5C9CBJJP=[Sean Allan, sean.allan@gmail.com, 1.0, Deactivated], default=[Sean Allan, sean.allan@gmail.com, 1.0, Deactivated], E6U13NFHGG=[Sean Allan, sean.allan@gmail.com, 1.0, Deactivated]}
1. key is SNAJHHVV8Q