Stackoverflow exception when trying to use custom JsonSerializer (Jackson)

Question

I am trying to serialize the object to JSON using Jackson, so that the field name is based on a type of field.

I have the same problem as the OP in this thread:

However, it's not working.

I am using Wildfly 10.1 Final

I did the following:

added resteasy-jackson2 dependency as provided to pom.xml.
Created CustomSerializer class as specified in the post I linked.

CustomSerializer class:

public class CustomSerializer extends JsonSerializer<Object> {
  public void serialize(Object value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
    jgen.writeStartObject();
    jgen.writeObjectField(value.getClass().getSimpleName(), value);
    jgen.writeEndObject();
  }
}

Added @JsonProperty("data") annotation to the object field, so my Response class now looks like this:

public class ResponseWithReturnValue extends Response {
    @JsonProperty("data")
    private Object object;

    public ResponseWithReturnValue (int code, String msg) {
        super(code, msg);
    }

    public Object getObject() {
        return object;
    }

    public void setObject(Object object) {
        this.object = object;
    }
}

When I test it I get the following json object:

{"code":0,"message":"Success","data":"test"}

So, the @JsonProperty annotation is working but the custom JsonSerializer isn't.

Now, I tried what was suggested in this blog, and added @JsonSerialize(using=CustomSerializer.class) annotation on my ResponseWithReturnValue class.

However, now I get this StackOverflow :) exception:

Exception in thread "main" java.lang.StackOverflowError
at java.lang.Class.getEnclosingMethodInfo(Class.java:1072)
at java.lang.Class.getEnclosingClass(Class.java:1272)
at java.lang.Class.getSimpleBinaryName(Class.java:1443)
at java.lang.Class.getSimpleName(Class.java:1309)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)
at com.fasterxml.jackson.core.base.GeneratorBase.writeObject(GeneratorBase.java:324)
at com.fasterxml.jackson.core.JsonGenerator.writeObjectField(JsonGenerator.java:1415)
at rs.netset.authority.web.facade.utils.CustomSerializer.serialize(CustomSerializer.java:13)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:130)
at com.fasterxml.jackson.databind.ObjectMapper.writeValue(ObjectMapper.java:2383)

I wasn't able to post full stacktrace because it's way too long.

Any ideas?

Well, serialize, serializeValue, writeValue, writeObject and writeObjectField are called indefinitely, so that's what's causing StackOverflowException, but I'm not sure what's the cause. — whatamidoingwithmylife, Dec 07 '17 at 01:43
Stack overflow is often caused by infinite recursion. This is the cause of your problem. — DwB, Dec 08 '17 at 16:30
When reviewing a stack trace to debug a recursion issue, include the top 10 - 15 lines, identify the repeating parts, then include the bottom 10 - 15 lines. — DwB, Dec 08 '17 at 16:33
`jgen.writeObjectField(value.getClass().getSimpleName(), value);` looks wrong. The first parameter is fieldname, not class name. — DwB, Dec 08 '17 at 16:36

score 2 · Answer 1 · answered Dec 11 '17 at 14:33

You have created an infinite recursion by always delegating to the same (your custom) serializer. The line jgen.writeObjectField(value.getClass().getSimpleName(), value); calls your custom serializer in order to serialize Object, which again calls jgen.writeObjectField(...) and so on.

You can delegate to another serializer or actually serialize the object:

jgen.writeObjectFieldStart("objectFieldName");
jgen.writeStringField("someValue", value.getSomeValue());
//...
jgen.writeEndObject();

Stackoverflow exception when trying to use custom JsonSerializer (Jackson)

1 Answers1