public class Test
{
  public static class Car
  {
      public String model;
      public Map<String, Integer> properties;
  }

  public static void main( String[] args )
  {
      Map<String, Integer> carProperties = new HashMap<>();
      carProperties.put("Speed", 100);
      carProperties.put("Weight", null);

      Car car = new Car();
      car.model = "F60";
      car.properties = carProperties;

      ObjectMapper mapper1 = new ObjectMapper();
      mapper1.setSerializationInclusion(JsonInclude.Include.NON_NULL);
      System.out.println("Test1: Include.NON_NULL on ObjectMapper");
      System.out.println("CarProperties -> " + mapper1.writeValueAsString(carProperties));
      System.out.println("Car           -> " + mapper1.writeValueAsString(car));
      System.out.println();

      ObjectMapper mapper2 = new ObjectMapper();
      mapper2.setSerializationInclusion(JsonInclude.Include.NON_NULL);
      mapper2.configOverride(Map.class).setInclude(JsonInclude.Value.construct(JsonInclude.Include.USE_DEFAULTS, JsonInclude.Include.USE_DEFAULTS));
      System.out.println("Test2: Include.NON_NULL on ObjectMapper and Include.USE_DEFAULTS override on Map class ");
      System.out.println("CarProperties -> " + mapper2.writeValueAsString(carProperties));
      System.out.println("Car           -> " + mapper2.writeValueAsString(car));
      System.out.println();

      ObjectMapper mapper3 = new ObjectMapper();
      mapper3.setSerializationInclusion(JsonInclude.Include.NON_NULL);
      mapper3.configOverride(Map.class).setInclude(JsonInclude.Value.construct(JsonInclude.Include.ALWAYS, JsonInclude.Include.ALWAYS));
      System.out.println("Test3: Include.NON_NULL on ObjectMapper and Include.ALWAYS override on Map class ");
      System.out.println("CarProperties -> " + mapper3.writeValueAsString(carProperties));
      System.out.println("Car           -> " + mapper3.writeValueAsString(car));
  }
}

Test1: Include.NON_NULL on ObjectMapper
CarProperties -> {"Speed":100}
Car           -> {"model":"F60","properties":{"Speed":100}}

Test2: Include.NON_NULL on ObjectMapper and Include.USE_DEFAULTS override on Map class 
CarProperties -> {"Speed":100,"Weight":null}
Car           -> {"model":"F60","properties":{"Speed":100}}

Test3: Include.NON_NULL on ObjectMapper and Include.ALWAYS override on Map class 
CarProperties -> {"Speed":100,"Weight":null}
Car           -> {"model":"F60","properties":{"Speed":100}}