Issue while using JoiObject Mapper

We are using JoiObjectMapper to convert a POJO class into Json String.
Jackson version : 2.8.x
The following is object mapper configuration :

import com.amazon.jacksonion.JoiObjectMapper;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.MapperFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.datatype.joda.JodaModule;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;


    public static ObjectMapper createObjectMapper() {        
        ObjectMapper mapper = new JoiObjectMapper();

        mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

        mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

        mapper.enable(MapperFeature.SORT_PROPERTIES_ALPHABETICALLY);

        mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);

        mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);

        mapper.registerModule(new JodaModule());

        mapper.registerModule(new JavaTimeModule());

        SimpleModule module = new SimpleModule();

        module.addSerializer(new JavaUtilDateSerializer());
        mapper.registerModule(module);
return mapper;
}

We are using objectMapper.writeValueAsString(object); method to convert the POJO into Json.

@Data
public class POJO {
@JsonProperty("a")
private String a;

@JsonProperty("b")
private String b;

}

Issue: While converting to string the object mapper is removing the double quotes from Json Key values.

Actual Output :

{
 a : "abc",
 b : "cde"
} 

Expected Output:

{
   "a" : "abc",
   "b" : "cde"
}

We need the json with double quotes. Can someone help us what are we missing here ??

I think you are looking for the boolean property JsonGenerator.Feature.QUOTE_FIELD_NAMES. If I am remembering well it was true by default some years ago. Maybe this has changed now. Try to set it true or false to see if it works.