Java 17: Trouble with Circular References in JSON Serialization Using Gson
I'm relatively new to this, so bear with me. After trying multiple solutions online, I still can't figure this out. I've searched everywhere and can't find a clear answer. I'm having a question with Gson's serialization when dealing with circular references in my Java 17 application. I have two classes that reference each other, which is causing a `com.google.gson.JsonSyntaxException` during serialization. Here’s a simplified version of my classes: ```java public class User { private String name; private Post post; // Getters and Setters } public class Post { private String title; private User author; // Getters and Setters } ``` When I attempt to serialize a `User` object that has a `Post` object which in turn references the `User`, I get the following behavior: ``` com.google.gson.JsonSyntaxException: cyclic reference ``` I've tried using `@Expose` annotations to control what gets serialized, but that didn't help. My goal is to include only the `User`'s name and the `Post`'s title in the JSON output to avoid cycling. I attempted to create a custom serializer for the `User` class: ```java public class UserSerializer implements JsonSerializer<User> { @Override public JsonElement serialize(User user, Type typeOfSrc, JsonSerializationContext context) { JsonObject jsonObject = new JsonObject(); jsonObject.addProperty("name", user.getName()); jsonObject.addProperty("postTitle", user.getPost() != null ? user.getPost().getTitle() : null); return jsonObject; } } ``` And registered this serializer with the Gson instance: ```java Gson gson = new GsonBuilder().registerTypeAdapter(User.class, new UserSerializer()).create(); ``` But I still encounter the cyclic reference scenario. I want to know how to effectively handle circular references in Gson, or if there’s a better approach or configuration I should consider to avoid this scenario altogether while correctly serializing my objects. Any insights would be appreciated! Is there a better approach? I'm coming from a different tech stack and learning Java. Any ideas what could be causing this? For reference, this is a production service.