StackOverflowError: null in both side relationship

Question

This is the first time I'm facing this problem. I have two entities with mutual relationships @OneToMany and @ManyToOne.

Team entity:

@Entity
@Data
public class Team {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String name;

    private String image;

    @OneToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER, mappedBy = "team")
    private List<Player> playerList = new ArrayList<>();
}

Player entity:

@Data
@Entity
public class Player {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String nickname;

    @ManyToOne
    private Team team;
}

I want to achieve that after saving the list of players to the team, players receive the record of this team to their table. After setting team to the player (so I know that this player is in the team) and getting list of players e.g. using this controller:

@RestController
@RequestMapping("/api")
@RequiredArgsConstructor
public class PlayerController {
    private final PlayerRepository playerRepository;

    @GetMapping("/player")
    public List<Player> getPlayers() {
        return playerRepository.findAll();
    }
}

I'm being faced with java.lang.StackOverflowError: null:

2020-03-15 21:58:48.419  WARN 8576 --- [nio-8080-exec-2] .w.s.m.s.DefaultHandlerExceptionResolver : Failure while trying to resolve exception [org.springframework.http.converter.HttpMessageNotWritableException]

java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
[...]

2020-03-15 21:58:48.423 ERROR 8576 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.http.converter.HttpMessageNotWritableException: Could not write JSON: Infinite recursion (StackOverflowError); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Infinite recursion (StackOverflowError) (through reference chain: com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->com.gottaaimfast.website.model.Player["team"]->com.gottaaimfast.website.model.Team["playerList"]->org.hibernate.collection.internal.PersistentBag[0]->[...] with root cause

java.lang.StackOverflowError: null
    at java.base/java.lang.ClassLoader.defineClass1(Native Method) ~[na:na]
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016) ~[na:na]
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:800) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:698) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:621) ~[na:na]
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:579) ~[na:na]
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521) ~[na:na]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:737) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:145) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:107) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.CollectionSerializer.serialize(CollectionSerializer.java:25) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:727) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719) ~[jackson-databind-2.9.8.jar:2.9.8]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:155) ~[jackson-databind-2.9.8.jar:2.9.8]
**AND IT LOOPS OVER AND OVER**

It seems like it bumps into some kind of loop but I have no idea why. I would be really thankful for every help!

Does this answer your question? [Infinite Recursion with Jackson JSON and Hibernate JPA issue](https://stackoverflow.com/questions/3325387/infinite-recursion-with-jackson-json-and-hibernate-jpa-issue) — Ervin Szilagyi, Mar 15 '20 at 21:34

Lesiak · Answer 1 · 2020-03-15T21:38:17.413

The loop is due to the fact that you are relying on default serialization to json. You have a bi-directional ManyToOne relationship, so:

For each player, you want to output his team
For the team, you output the players in the team

and thus yoy have a cycle in your serialization process.

Your options are:

use @JsonIgnore on one side of the ManyToOne relationship to break the cycle
use a custom DTO With no cycles to transfer the data
Use @JsonManagedReferenceand @JsonBackReference

Nonika · Accepted Answer · 2020-03-15T22:31:33.527

2

this bidirectional json mapping problem add these annotations to your entities corresponding fields

In Player:

    @ManyToOne
    @JsonManagedReference
    private Team team;

In Team:

    @JsonBackReference
    @OneToMany(cascade = CascadeType.REMOVE, fetch = FetchType.EAGER, mappedBy ="team")
    private List<Player> playerList = new ArrayList<>();

See this answer:

Prevent recursive association in ManyToOne hibernate

edited Mar 15 '20 at 22:31

answered Mar 15 '20 at 21:32

Nonika

2,490
13
15

Using these annotations my `playerList` is not being returned anymore. :/ – ProbDed Mar 15 '20 at 22:10
Yes you have to break somewhere the recursion,. As you have playerRepository.findAll(), I thought that you need player->team. This is the purpose of this annotation to tell the serializer the backReferences not follow to – Nonika Mar 15 '20 at 22:14
if you want playerList it would be better to start from teamRepository I think – Nonika Mar 15 '20 at 22:15

StackOverflowError: null in both side relationship

2 Answers2