code: public static String float2str(final float floatValue, final int radix) {
      if (radix != 10 && radix != 16) {
        throw new IllegalArgumentException("Illegal radix [" + radix + ']');
      }
      final String result;
      if (radix == 16) {
        String converted = Double.toHexString(floatValue);
        boolean minus = converted.startsWith("-");
        if (minus) {
          converted = converted.substring(1);
        }
        if (converted.startsWith("0x")) {
          converted = converted.substring(2);
        }
        result = (minus ? '-' + converted : converted).toUpperCase(Locale.ENGLISH);
      } else {
        result = Double.toString(floatValue);
      }
      return result;
    }
docs: Convert float value into string representation with defined radix
  base.
  
  @param floatValue value to be converted in string
  @param radix      radix base to be used for conversion, must be 10 or 16
  @return converted value as upper case string
  @throws IllegalArgumentException for wrong radix base
  @since 1.4.0