Excluding certain fields from Serialization based on value in GSON

The way to achieve this is by creating custom serializer for the class in question. After allowing Gson to create a JSON object in default fashion, remove the property that you want to exclude based on its value.

public class SerializerForMyClass implements JsonSerializer<MyClass> {  

    @Override
    public JsonElement serialize(MyClass obj, Type type, JsonSerializationContext jsc) {
        Gson gson = new Gson();
        JsonObject jObj = (JsonObject)gson.toJsonTree(obj);   
        if(obj.getMyProperty()==0){
            jObj.remove("myProperty");
        }
        return jObj;
    }
}

And registering the new serializer in the Gson object that you use for serialization in the application for this class.

GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(MyClass.class, new SerializerForMyClass());
Gson gson=gsonBuilder.create();
gson.toJson(myObjectOfTypeMyClass);

This is how I use a type adapter to avoid serializing boolean values that are false. It avoids creating an additional Gson instance and does not rely on specific field names.

class MyClassTypeAdapter: JsonSerializer<MyClass>{
   override fun serialize(myObject: MyClass, type: Type, context: JsonSerializationContext): JsonElement {
      val jsonElement = context.serialize(myObject)

      jsonElement.asJsonObject.entrySet().removeAll { it.value is JsonPrimitive && (it.value as JsonPrimitive).isBoolean && !it.value.asBoolean }

      return jsonElement
   }
}