Alina Ricciuti ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=61fb92a... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiMDMxNWIyYTg4... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16169?atlOrigin=eyJpIjoiMDMxNW... ) HHH-16169 ( https://hibernate.atlassian.net/browse/HHH-16169?atlOrigin=eyJpIjoiMDMxNW... ) NullPointerException when merging detached collections due to LOG.debugf ( https://hibernate.atlassian.net/browse/HHH-16169?atlOrigin=eyJpIjoiMDMxNW... ) Issue Type: Bug Assignee: Unassigned Created: 10/Feb/2023 09:21 AM Environment: Hibernate: 6.1.6, 6.1.7 Postgresql: 11 Spring Data JPA: 3.0.1 Spring Boot: 3.0.2 JDK: Oracle OpenJDK 17.0.2 OS: Windows 11 Priority: Major Reporter: Alina Ricciuti ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=61fb92a... ) I have difficulties migrating my backend application from hibernate 5.4.32 to hibernate 6 due to : java.lang.NullPointerException: Cannot invoke "org.hibernate.persister.collection.CollectionPersister.getRole()" because "this.loadedPersister" is null Please find below a simplified datamodel explaining my issue. Note that I am using Lombok / Spring Data. * Customer having Sales @Getter @Setter @Entity @Table(name = "CUSTOMER") @SequenceGenerator(name = "SEQ_CUSTOMER_ID", allocationSize = 10, sequenceName = "SEQ_CUSTOMER_ID") public class Customer { @Id @Column(name = "ID") @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_CUSTOMER_ID") private Long id; @Column(name = "NAME") private String name; @OneToMany(mappedBy = "customer", cascade = CascadeType.ALL, orphanRemoval = true) private List<Sale> sales = new ArrayList<>(); } * Sale @Getter @Setter @Entity @Table(name = "SALE") @SequenceGenerator(name = "SEQ_SALE_ID", allocationSize = 10, sequenceName = "SEQ_SALE_ID") public class Sale { @Id @Column(name = "ID") @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_SALE_ID") private Long id; @Column(name = "INDENTIFIER") private String indentifier; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "ID_CUSTOMER") private Customer customer; @OneToMany(mappedBy = "sale", cascade = CascadeType.ALL) private List<SaleLine> saleLines = new ArrayList<>(); } * SaleLine @Data @ToString(exclude = {"sale"}) @Entity @Table(name = "SALELINE") @SequenceGenerator(name = "SEQ_SALELINE_ID", allocationSize = 10, sequenceName = "SEQ_SALELINE_ID") public class SaleLine { @Id @Column(name = "ID") @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SEQ_SALELINE_ID") private Long id; @Column(name = "INDENTIFIER") private String identifier; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "ID_SALE", nullable = false) private Sale sale; } My unit test is trying to create a customer in 2 steps : first, creating the customer, then adding the sale with a sale line. @Test public void add_customer_sale_ko_collection() { // first creating the customer Customer customer = new Customer(); customer.setName("Customer Z"); customer = customerRepository.save(customer); // then adding the sale Sale sale = new Sale(); sale.setIndentifier("Customer Z sale"); SaleLine saleLine = new SaleLine(); saleLine.setIdentifier("some product sold"); saleLine.setSale(sale); sale.getSaleLines().add(saleLine); customer.getSales().add(sale); sale.setCustomer(customer); customerRepository.save(customer); } The framework throws a NullPointerException when logging the CollectionEntry due to null values. I have attached the full stack. If needed, I cas share my sample project. ( https://hibernate.atlassian.net/browse/HHH-16169#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16169#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100215- sha1:a0f3b6a )