I'm tryng to print the object that I get from the database but everytime it give me the StackOverFlowError:

    SLF4J: Failed toString() invocation on an object of type [java.util.ArrayList]
Reported exception:
java.lang.StackOverflowError
    at java.base/java.lang.StringBuilder.<init>(StringBuilder.java:102)
    at com.example.NetflixProve.model.Tracker.toString(Tracker.java:116)
    at java.base/java.lang.String.valueOf(String.java:4215)
    at java.base/java.lang.StringBuilder.append(StringBuilder.java:169)
    at com.example.NetflixProve.model.Channel.toString(Channel.java:33)
    at java.base/java.lang.String.valueOf(String.java:4215)
    at java.base/java.lang.StringBuilder.append(StringBuilder.java:169)
    at java.base/java.util.AbstractCollection.toString(AbstractCollection.java:457)
    at org.hibernate.collection.internal.PersistentBag.toString(PersistentBag.java:622)
    at java.base/java.lang.String.valueOf(String.java:4215)
....

same even if I use System.out.println();

I deleted @Data and added @JsonBackedReference but it didn't work. My code in entities are:

@Entity
@Table(name= "TBL_CHANNEL")
@Getter
@Setter

public class Channel {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Generated(GenerationTime.ALWAYS)
    private Long id;

    @ManyToOne
    @JoinColumn(name = "channels")
    @JsonBackReference
    private Tracker tracker;
    @Column(name = "Channel_Name")
    private String channelName;

    @Override
    public String toString() {
        return "Channel{"  
                "id="   id  
                ", tracker="   tracker  
                ", channelName='"   channelName   '\''  
                '}';
    }
}

and:

@Entity
@Table(name = "TBL_TRACKER")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Tracker {
    @Id
    @Column(name = "ARCHIVE_ID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Generated(GenerationTime.ALWAYS)
    private Long archiveId;

    @Column(name = "NOTIFICATION_ID")
    private String notificationId;

    @Column(name = "NOTIFICATION_ID_INDEX")
    private String notificationIdIndex;

    @Column(name = "DELIVERY_CHANNEL")
    @Enumerated(EnumType.STRING)
    private DeliveryChannel deliveryChannel;

    @Column(name = "SENDING_DATE")
    @DateTimeFormat
    private Date sendingDate;

    @Column(name = "SERVICE_ID")
    private String serviceId;

    @Column(name = "IDENTIFIER_TYPE")
    @Enumerated(EnumType.STRING)
    private IdentifierType identifierType;

    @Column(name = "IDENTIFIER")
    private String identifier;//fiscalCode

    @Column(name = "PAN")
    private String pan;


    @Column(name = "FLAG")
    @Enumerated(EnumType.STRING)
    private FlagEnum flag;

    @Column(name = "NOTIFICATION_CATEGORY")
    @Enumerated(EnumType.STRING)
    private NotificationCategory notificationCategory;

    @Column(name = "EXPIRING_DATE")
    @DateTimeFormat
    private Date expiringDate;

    @Column(name = "CREATION_DATE")
    @DateTimeFormat
    @CreationTimestamp
    private Date creationDate;

    @Column(name = "VISUALIZATION_DATE")
    @DateTimeFormat
    private Date visualizationDate;

    @Column(name = "EXPIRE_VISUALIZATION_DATE")
    @DateTimeFormat
    private Date expireVisualizationDate;


    @Column(name = "portal")
    private PortalEnum portalEnum;

    @Column(name = "campaign_name")
    private String campaignName;

    @Column(name = "business_priority")
    private int businessPriority;

    @OneToMany(cascade = {CascadeType.ALL},mappedBy = "tracker")
       @JsonManagedReference
    private List<Channel> channelsId;



    @Override
    public String toString() {
        return "Tracker{"  
                "archiveId="   archiveId  
                ", notificationId='"   notificationId   '\''  
                ", notificationIdIndex='"   notificationIdIndex   '\''  
                ", deliveryChannel="   deliveryChannel  
                ", sendingDate="   sendingDate  
                ", serviceId='"   serviceId   '\''  
                ", identifierType="   identifierType  
                ", identifier='"   identifier   '\''  
                ", pan='"   pan   '\''  
                ", flag="   flag  
                ", notificationCategory="   notificationCategory  
                ", expiringDate="   expiringDate  
                ", creationDate="   creationDate  
                ", visualizationDate="   visualizationDate  
                ", expireVisualizationDate="   expireVisualizationDate  
                ", portalEnum="   portalEnum  
                ", campaignName='"   campaignName   '\''  
                ", businessPriority="   businessPriority  
                ", channelsId="   channelsId  
                '}';
    }

The error happen here, when I'm trying to get the code, (later I will use the DTO to print)

public List<Tracker> findAll(){
    List<Tracker> trackerList= trackerRepo.findAll();
    log.info("tracker: {}",trackerList);
    return trackerList;
}

CodePudding user response：

You can use @Data, just add @ToString.Exclude to the tracker member of Channel. The point is to not have any circular paths while invoking toString.