How to use Random Access file

import java.io.File;
import java.io.RandomAccessFile;
import java.io.IOException;

public class DemoRandomAccessFile {

    private static void doAccess() {

        try {
     
            File file = new File("DemoRandomAccessFile.out");
            RandomAccessFile raf = new RandomAccessFile(file, "rw");

            // Read a character
            byte ch = raf.readByte();
            System.out.println("Read first character of file: " + (char)ch);

            // Now read the remaining portion of the line.
            // This will print out from where the file pointer is located
            // (just after the '+' character) and print all remaining characters
            // up until the end of line character.
            System.out.println("Read full line: " + raf.readLine());

            // Seek to the end of file
            raf.seek(file.length());

            // Append to the end of the file
            raf.write(0x0A);
            raf.writeBytes("This will complete the Demo");
            raf.close();
          
        } catch (IOException e) {
            System.out.println("IOException:");
            e.printStackTrace();
        }
    }
 
    public static void main(String[] args) {
        doAccess();
    }

}
}