Problem reading random access file

Hi all. I am trying to develop a program that will shutdown a group of
computers attached to a network using using a java application. I am
writing the room numbers and the number of computers per a room within
a random access file which the program will then read back in. I have
managed to get it to read the first two numbers of the file but then
then next number is a number that is not in the fie. Below is the code
that I am using:

    public void readData() {
        byte by = 2;
        try {
            File f = new File("Class Room Details.rsh");
            RandomAccessFile raf = new RandomAccessFile(f, "r");

            raf.skipBytes(by);
            System.out.println("the first read is: " +
raf.readByte());
            raf.skipBytes(by = 4);
            System.out.println("the second read is: " +
raf.readByte());
        } catch (IOException r) {
            System.err.println("The read error is: " + r.toString());
        }
    }

Any help in this matter would be appreciated