code: @Override
      protected String getDefaultTimeFormatIfNull(Member c2jMemberDefinition, Map<String, Shape> allC2jShapes,
                                                  String protocolString, Shape parentShape) {
  
          validateTimestampProtocol(protocolString, c2jMemberDefinition.getTimestampFormat(), c2jMemberDefinition.getShape());
  
          String shapeName = c2jMemberDefinition.getShape();
          Shape shape = allC2jShapes.get(shapeName);
  
          validateTimestampProtocol(protocolString, shape.getTimestampFormat(), shapeName);
  
          return super.getDefaultTimeFormatIfNull(c2jMemberDefinition, allC2jShapes, protocolString, parentShape);
      }
docs: Throw exception if timestamp format is provided for non-json protocol.