Convert string to Bytes

How to convert string to Bytes

 public static byte[] stringToBytesUTFCustom(String str) {

        byte[] b = new byte[str.length() << 1];

        for (int i = 0; i < str.length(); i++) {

            char strChar = str.charAt(i);

            int bpos = i << 1;

            b[bpos] = (byte)((strChar & 0xFF00) >> 8);

            b[bpos + 1] = (byte)(strChar & 0x00FF);

        }

        return b;

    }