1 piyush    pankaj    04mathematic10physics   20biology   45
2 vanitha   reddy     03physics   30chemistry 60
3 deepesh   shetty    05chemistry 5 biology   45
4 jane      dsouja    01geography 30chemistry 60biology   45
5 ramadasa  hegde     02chemistry 80biology   70

05  ID                         PIC 99.
05  FNAME                      PIC X(10).
05  LNAME                      PIC X(10).
05  NO_SUB                     PIC X(2).
05  SUBJECTS OCCURS 0 TO 10 TIMES
          DEPENDING ON NO_SUB
       10  SUB_NAME            PIC X(10).
       10  MARKS               PIC 99.

1 piyush    pankaj    04mathematic10
1 piyush    pankaj    04physics   20
1 piyush    pankaj    04biology   70
2 vanitha   reddy     03physics   30
2 vanitha   reddy     03chemistry 60
3 deepesh   shetty    05chemistry  5
3 deepesh   shetty    05biology   45
4 jane      dsouja    01geography 30
4 jane      dsouja    01chemistry 60
4 jane      dsouja    01biology   70
5 ramadasa  hegde     02chemistry 80
5 ramadasa  hegde     02biology   70

05  ID                         PIC 99.
05  FNAME                      PIC X(10).
05  LNAME                      PIC X(10).
05  NO_SUB                     PIC X(2).
05  SUBJECTS OCCURS 0 TO 10 TIMES
          DEPENDING ON NO_SUB
       10  SUB_NAME            PIC X(10).
       10  MARKS               PIC 99.

Byte 1 for a length of 24 + Byte 25 for a length of 12
Byte 1 for a length of 24 + Byte 37 for a length of 12

5 ramadasa  hegde     02chemistry 80
5 ramadasa  hegde     02biology   70

String id = inputLine.substr(1,2);
String firstName = inputLine.substr(3,12);
String lastName  = inputLine.substr(13,22);
String numberOfEntriesStr = inputLine.substr(23,24);

int numberOfEntries = Integer.parseInt(numberOfEntriesStr);

for (int i = 0; i < numberOfEntries) {
   ...
}