Java tutorial
import java.io.*; public class Main { public static void main(String[] args) { try { byte[] b = { 1, 2, 3, 4, 5, 6 }; RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw"); // write 2 bytes in the file raf.write(b, 2, 2); // set the file pointer at 0 position raf.seek(0); // print the two bytes we wrote System.out.println(raf.readByte()); System.out.println(raf.readByte()); raf.close(); } catch (IOException ex) { ex.printStackTrace(); } } }