code: public static byte[] decode(byte[] source, int options) {
          if (source == null) {
              throw new IllegalArgumentException("Cannot decode null source array.");
          }
          return decode(source, 0, source.length, options);
      }
docs: Decode the Base64-encoded data in input and return the data in a new
  byte array.
  
  The padding '=' characters at the end are considered optional, but if
  any are present, there must be the correct number of them.
  
  @param source The data to decode
  @param options controls certain features of the decoded output. Pass
  DEFAULT to decode standard Base64.
  @return decoded data