Java tutorial
import java.io.*; public class Main { public static void main(String[] args) { try { long l = 12345676789098L; RandomAccessFile raf = new RandomAccessFile("c:/test.txt", "rw"); // write something in the file raf.writeLong(l); // set the file pointer at 0 position raf.seek(0); System.out.println(raf.readLong()); // set the file pointer at 0 position raf.seek(0); // write something in the file raf.writeLong(12345676789099L); raf.seek(0); System.out.println(raf.readLong()); } catch (IOException ex) { ex.printStackTrace(); } } }