import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
public class MainClass {
public static void main(String args[]) {
FileOutputStream fileOutputStream;
FileChannel fileChannel;
ByteBuffer byteBuffer;
try {
fileOutputStream = new FileOutputStream("test.txt");
fileChannel = fileOutputStream.getChannel();
byteBuffer = ByteBuffer.allocateDirect(26);
for (int i = 0; i < 26; i++)
byteBuffer.put((byte) ('A' + i));
byteBuffer.rewind();
fileChannel.write(byteBuffer);
fileChannel.close();
fileOutputStream.close();
} catch (IOException exc) {
System.out.println(exc);
}
}
}