How to make code portable

Question

Hi,
I have a question like how can one make the following java code portable on different enviroments. What are the parts of the code that are not portable and how to rewrite the code in more portable manner.
Here is the code.
import java.io.IOException;
import java.io.RandomAccessFile;
* Some not very portable Java code. This code obtains a letter from the user
* and gets a corresponding integer from a binary array stored in a file. The
* value "base" is the starting position for the array in the file. The method
* "readbyte" reads one byte from the file at a given position. This code is
* assumed to occur within method Main of a public Java class.
public class Portable {
     public static void main(String args[])throws IOException  {
          int letter, start, base=0, val;
          int inbuf[] = new int[50];
          byte inb;
          RandomAccessFile ra = new RandomAccessFile("abc.txt","rw");
          //DataInputStream dr = new DataInputStream(fr);
          System.out.print("Enter a letter between A and Z: ");
          letter = (int) System.in.read();
          if ((letter >= (int) 'a') && (letter <= (int) 'a' + 25)) {
               letter = letter - 32;
          if ((letter >= (int) 'A') && (letter <= (int) 'A' + 25)) {
               start = base + 4 * (letter - (int) 'A');
               val = 0;
               for (int pos = start; pos < start + 4; pos++) {
                    ra.seek(pos);
                    inb = ra.readByte();
                    val = (val << 8) + ra.readByte();
               System.out.println("The value stored at position " + letter
                         + " is " + val);
}Any help would be great.
Thanx.

Answer 1

I can't see any code which stores any data, but the byte order for an int can be different on different platforms, but that's more related to the format of the file.
Kaj