code: public static FileMessage decode(String encodedMessage, File file) throws IOException {
  		return decode(
  			encodedMessage.isEmpty()
  			? ByteArray.EMPTY_BYTE_ARRAY
  			: new ByteArray(
  				Base64Coder.decode(
  					encodedMessage
  				)
  			),
  			file
  		);
  	}
docs: base-64 decodes the message into the provided file.
  
  @see #decode(com.aoindustries.messaging.ByteArray, java.io.File)