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My problem is similar to this one https://discourse.hibernate.org/t/hibernate-throws-org-hibernate-id-identifiergenerationexception-attempted-to-assign-id-from-null-one-to-one-property/1777 but I am getting a different exception after applying the answer from this thread.

My entities:

@Entity
@Table(name = "location")
public class Location {

    @Id
    private Long id;

    @Column(name = "country_code")
    private String countryCode;

    private Double longitude;

    private Double latitude;

    @OneToOne(fetch = FetchType.LAZY)
    @MapsId
    private Distributor distributor;

    public Distributor getDistributor() {
        return distributor;
    }

// here I apply the advice from the linked thread above
    public void setDistributor(Distributor distributor) {
        this.distributor = distributor;
        this.id = distributor.getId();
    }
// other getters/setters
}
@Entity
@Table
public class Distributor {

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

    private String name;
    private String site;

    @OneToOne(
            mappedBy = "distributor",
            cascade = CascadeType.ALL,
            orphanRemoval = true,
            fetch = FetchType.LAZY,
            optional = false
    )
    private Location location;

// getters/setters/constructor

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Distributor )) return false;
        Distributor that = (Distributor ) o;
        return Objects.equals(id, that.id);
    }

    @Override
    public int hashCode() {
        return id != null ? id.hashCode() : 0;
    }

}

Controller with corresponding Spring Data Repository:

    @PostMapping
    public ResponseEntity<Distributor> test(@RequestBody Distributor distributor) {
        distributor.getLocation().setDistributor (distributor);

        return ResponseEntity.ok(repository.save(distributor));
    }

With this payload:

{
    "name" : "name1",
    "location" : {
        "countryCode" : "US",
        "longitude" : 34 ,
        "latitude" : 12
    }
}

I am getting an endless nested response with proper fields(distributor -> location -> distributor -> location ..), which ends with SO Error:

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:741) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:723) ~[jackson-databind-2.11.0.jar:2.11.0]
    at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:166) ~[jackson-databind-2.11.0.jar:2.11.0]
....

I can't fathom why does this happen, I followed all available tutorials.

2 Answers 2

3

That's because there is a cyclic dependency between Location and Distributor.

As both have reference to each other, they keep serializing inner reference.

You can avoid that using jackson annotation @JsonBackReference and @JsonManagedReference.

JsonBackReference: skips serialization of annotated property

JsonManagedReference : forward reference and serializes annotated property

In your case, this should work.

//Distributor class
@JsonManagedReference
private Location location;

//Location class 
@JsonBackReference
private Distributor distributor;
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4 Comments

Could you tell, if I were to pass this payload via dto to the entity, this problem wouldn't even happen, right?
@improbable problem is with this part ResponseEntity.ok(repository.save(distributor)) when returning the response. that's when Jackson trying to serialize object to json and failing.
I see, so if I were to pass corresponding dto, which doesn't contain this relationship but plain fields instead of entity this shouldn't happen.
Correct. you can create a response model for distributor and location and they shouldn't have a cyclic dependency. then it won't happen. Other wise you can always use these annottaions. :)
1

In my case, I had two entities in relationship with each other, so if I created an object of one of them, I fell in some infinite JSON resonse loop.

I solved that problem with @JsonIgnore annotation at the top of the @ManyToMany relationship like:

@JsonIgnore
@ManyToMany(mappedBy = "drugs") 
private Set<Pharmacy> pharmacies;

and

@JsonIgnore
@ManyToMany(cascade = CascadeType.DETACH, fetch = FetchType.EAGER)
@JoinTable( name = "pharmacy_drug", joinColumns = @JoinColumn(name =
                "pharmacy_id", referencedColumnName = "id"), inverseJoinColumns
                = @JoinColumn(name = "drug_id", referencedColumnName = "id"))
private Set<Drug> drugs;

Comments

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