Fetching Entities described via @EmbeddedId in Spring Batch and with JpaCursorItemReader returns always single value

[dari220]

Bug description Fetching Entities(UserRole in ManyToOne association) described via jakarta.persistence.EmbeddedId in Spring Batch and with JpaCursorItemReader returns always a single value.

Example: User has two UserRoles with roleId1=1 and roleId2=4. In ItemProcessor I get always either roleId1 or roleI2 but not both.

Environment Spring boot 3.1.3, Spring Batch 5.0.3, Hibernate-Core 6.2.7

Entities

@Entity
@Table( name = "user"
})
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class User extends PersonExtendedImpl implements UserDetails, ToDto<UserDTO>, Serializable {

 
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name = "User_ID")
    private Integer id;
		

    @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
    @OneToMany(
            mappedBy = "user",
            cascade = CascadeType.ALL,
            orphanRemoval = true)
	private List<UserRole> userRoles = new ArrayList<UserRole>();

        equals, hashcode, getter, setter

@Entity
@Table(name = "user_role",
	   uniqueConstraints={@UniqueConstraint(columnNames = {"User_ID", "Role_ID"})}
)
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class UserRole implements Serializable {

	@EmbeddedId
        private UserRoleKey id;
	
	@Setter(AccessLevel.NONE)
	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "User_ID", referencedColumnName = "User_ID", insertable=false, updatable=false)
	private User user;
	
	public UserRole(UserRoleKey id) {	
		this.id = id;
	}
        equals, hashcode, getter, setter
}

@Embeddable
public class UserRoleKey implements Serializable {

   @Column(name = "User_ID")
    private Integer userId;

   @Column(name = "Role_ID")
    private Integer roleId;
    
   equals, hashcode, getter, setter
}

Steps to reproduce

	@Bean
	@Scope("prototype")
	Step step( JobRepository jobRepository,
		JpaCursorItemReader<User> userPrivilegeReader,
		CustomerPrivilegeProcessor userPrivilegeProcessor,
		PlatformTransactionManager userTransactionManager) throws Exception {
		
	    return new StepBuilder("customerPrivilegeStep", jobRepository)

		        .<User, User> chunk(10, userTransactionManager)
		        .reader( userPrivilegeReader )
		        .processor( userPrivilegeProcessor )
		        .writer(() -> System.out.println("NOT OKAY  "))
		        .build();
	}

This Step produces correct sql statement but just one UserRole fetched in List of userRoles.

SQL:

			"""
				SELECT u from User u 
				JOIN FETCH u.userRoles ur 
				WHERE u.expiresAt > CURRENT_TIMESTAMP 
				AND u.enabled = true 
				AND u.locked = false """

select u1_0.User_ID,u1_0.Auth_Type,u1_0.Birth_day,u1_0.Country_ID,u1_0.Email,u1_0.Enabled,u1_0.Expires_at,u1_0.First_Name,u1_0.Form_of_Address_ID,u1_0.Last_accessed_at,u1_0.Last_Name,u1_0.Last_updated_at,u1_0.Locked,u1_0.Locked_at,u1_0.Password,u1_0.Phone,u1_0.Registered_at,u1_0.Register_Type,u2_0.User_ID,u2_0.Role_ID,u1_0.Username 
from user u1_0 
join user_role u2_0 on u1_0.User_ID=u2_0.User_ID 
where u1_0.Expires_at>current_timestamp(6) 
and u1_0.Enabled=1 and u1_0.Locked=0

Important! I could not reproduce the same issue in Spring Boot 3.1.3 and Spring MVC application environment!!!

Expected behavior JpaItemReaders should fetch all associated Entities(UserRole's) into Collection of parent Entity(User).