How to Resolve HibernateException: Found Shared References to a Collection

Question

Why am I encountering the HibernateException: Found shared references to a collection while trying to manage related entities in Hibernate?

person.addToRelatedPersons(anotherPerson);
anotherPerson.addToRelatedPersons(person);
anotherPerson.save();
person.save();

Answer

The HibernateException: Found shared references to a collection typically occurs when Hibernate detects that one or more entities reference a shared collection. This scenario primarily arises in bidirectional relationships where both sides of the relationship attempt to manage the same collection. In your case, the error points to the shared references between two 'Person' entities.

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

    @ManyToMany(cascade = CascadeType.ALL)
    private Set<Person> relatedPersons = new HashSet<>();

    public void addToRelatedPersons(Person person) {
        this.relatedPersons.add(person);
        person.getRelatedPersons().add(this);
    }

    public Set<Person> getRelatedPersons() {
        return relatedPersons;
    }
}

Causes

  • Both entities are trying to add each other into a shared collection without proper lifecycle management.
  • Hibernate does not support recursive references without correctly defined relationships in its configuration.
  • Modification of collections should be managed carefully to ensure that Hibernate can track changes.

Solutions

  • Ensure that the adding/removing of related objects is managed through one side of the relationship, usually the owning side.
  • Consider using methods that manage both sides of the relationship (one entity at a time) by calling a method on one side, thus maintaining control over the relationship.
  • Use @Transactional annotations if you are performing database operations within a transactional context to prevent state inconsistencies.

Common Mistakes

Mistake: Not managing both sides of the relationship correctly.

Solution: Use a dedicated method to manage both sides properly to avoid shared references.

Mistake: Calling `save()` methods without ensuring transaction management.

Solution: Always wrap database operations within a transaction to ensure consistency.

Helpers

  • HibernateException
  • shared references collection error
  • Hibernate collection management
  • bidirectional relationships Hibernate
  • Hibernate save method errors

Related Questions

⦿How to Resolve IntelliJ IDEA Not Recognizing JAVA_HOME for Gradle Configuration

Learn to fix IntelliJ IDEA not recognizing JAVAHOME for Gradle. Stepbystep solutions common pitfalls explained.

⦿How to Convert a Java String to an ASCII Byte Array?

Learn how to convert a Java String to an ASCII byte array with stepbystep instructions and code examples.

⦿How to Sort a Java Collection of Custom Objects by ID

Learn how to sort a Java collection of custom objects by their ID field using Comparator or Comparable.

⦿What Java Library Should I Use for Base64 Encoding/Decoding in Production?

Explore the best Java libraries for stable Base64 encoding and decoding in production environments.

⦿How to Use Hamcrest to Assert Multiple Valid Outcomes in JUnit

Learn how to assert multiple valid results using Hamcrest matchers with JUnit for flexible testing in Java.

⦿How to Write Files to a Specific Folder on an SD Card in Android?

Learn how to write files to a specific folder on an SD card in Android with sample code and best practices.

⦿How to Pass an ArrayList of Parcelable Objects to a Fragment in Android

Learn how to effectively pass an ArrayList of Parcelable objects to an Android Fragment and troubleshoot common issues.

⦿Comparing Performance: ConcurrentHashMap vs HashMap in Java

Explore the performance differences between ConcurrentHashMap and HashMap focusing on the .get operation and scenarios with low data volume.

⦿Why Does This Java 8 Lambda Expression Fail to Compile?

Explore why a Java 8 lambda expression fails to compile alongside detailed explanations and code snippets for clarity.

⦿How to Create an Empty Multi-Module Maven Project

Learn the stepbystep process to create an empty multimodule Maven project without using deprecated methods.

© Copyright 2025 - CodingTechRoom.com

close