import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class MainClass {
public static void main(String args[]) {
RandomAccessFile randomAccessFile;
FileChannel fileChannel;
ByteBuffer byteBuffer;
try {
randomAccessFile = new RandomAccessFile("test.txt", "rw");
fileChannel = randomAccessFile.getChannel();
byteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, 26);
for (int i = 0; i < 10; i++)
byteBuffer.put((byte) ('A' + i));
fileChannel.close();
randomAccessFile.close();
} catch (IOException exc) {
System.out.println(exc);
System.exit(1);
}
}
}