BufferOverflowException problem

I am using MappedByteBuffer. This code cause this annoying exception:

Code:

---

import java.io.*;
import java.util.*;
import java.nio.channels.*;
import java.nio.*;

class Lab3d
{
    public static void main(String[] args) throws Exception
    {
                long start;
                long end;

                RandomAccessFile fio = new RandomAccessFile ("C:\\temp2.txt", "rw");
                FileChannel fc = fio.getChannel ();
            MappedByteBuffer buffer = fc.map (FileChannel.MapMode.READ_WRITE, 0, (int) fc.size ());

                start = System.currentTimeMillis ();

                buffer.putInt (10);

                fio.close ();

                end = System.currentTimeMillis ();
        }
}

---