I am using Jackson ObjectMapper to (de)serialize a class with polymorphic nested class. The deserialization of JSON to the class is working fine but when I try to serialize the class to JSON using writeValueAsString function I observe duplicate values in the output
public class Movie {
private String movieName;
@JsonTypeInfo(use=Id.NAME,include=As.EXTERNAL_PROPERTY,property="movieName")
@JsonSubTypes({@JsonSubTypes.Type(value = StarWarsParams.class, name = "starwars")})
private MovieParams movieParams;
/* Getters and setters follow */
}
/* Empty class */
public class MovieParams {
}
public class StarWarsParams extends MovieParams{
private String characterName;
@JsonTypeInfo(use=Id.NAME,include=As.EXTERNAL_PROPERTY,property="characterName")
@JsonSubTypes({@JsonSubTypes.Type(value = SithParameters.class, name = "Darth Vader")})
private CharacterParams characterParams;
/* Getters and setters follow */
}
/* Empty class */
public class CharacterParams {
}
public class SithParameters extends CharacterParams {
private boolean canShootLightning;
}
The code snippet where the conversion is done as follows:
Movie movie = new Movie();
movie.setMovieName("starwars");
StarWarsParams starWarsParams = new StarWarsParams();
starWarsParams.setCharacterName("Darth Vader");
SithParameters sithParameters = new SithParameters();
sithParameters.setCanShootLightning(false);
starWarsParams.setCharacterParams(sithParameters);
movie.setMovieParams(starWarsParams);
ObjectMapper mapper = new ObjectMapper();
String jsonStringSample = mapper.writeValueAsString(movie);
System.out.println(jsonStringSample);
The output, in which movieName and characterName have duplicates are as follows:
{"movieName":"starwars","movieParams":{"characterName":"Darth Vader","characterParams":{"canShootLightning":false},"characterName":"Darth Vader"},"movieName":"starwars"}