Convert double to byte array in Java

/*from   w  ww . j a v a  2s  .c om*/
import java.nio.ByteBuffer;

public class Main {

  
  public static byte[] convertToByteArray(double value) {
      byte[] bytes = new byte[8];
      ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
      buffer.putDouble(value);
      return buffer.array();

  }
  

  public static void main(String[] argv) {
    System.out.println(convertToByteArray(21.3F));
  }
}