StackOverflow during merge of pair of detached entities in JBoss EAP

Issue

• A "many to many" association (e.g. between Employee and Task in the example below) is defined using an intermediate entity (e.g. TaskParticipant in the example below).
• The intermediate entity uses an {{@Embeddable}} (primary) key that maps a ManyToOne} association with both classes.
• During merge of a detached entity on one side of the association (e.g. Employee), a non-terminating, recursive load loop is initiated resulting in an eventual java.lang.StackOverflowError.

• The repeating portion of the stack is shown below:

  ... java.lang.StackOverflowError
          ...
          at org.hibernate.internal.SessionImpl.fireLoadNoChecks(SessionImpl.java:1277)
          at org.hibernate.internal.SessionImpl.immediateLoad(SessionImpl.java:1119)
          at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:178)
          at org.hibernate.proxy.AbstractLazyInitializer.getIdentifier(AbstractLazyInitializer.java:89)
          at org.hibernate.type.EntityType.getHashCode(EntityType.java:372)
          at org.hibernate.type.ComponentType.getHashCode(ComponentType.java:242)
          at org.hibernate.engine.spi.EntityKey.generateHashCode(EntityKey.java:61)
          at org.hibernate.engine.spi.EntityKey.<init>(EntityKey.java:54)
          at org.hibernate.internal.AbstractSharedSessionContract.generateEntityKey(AbstractSharedSessionContract.java:524)
          at org.hibernate.loader.Loader.extractKeysFromResultSet(Loader.java:879)
          at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:729)
          at org.hibernate.loader.Loader.processResultSet(Loader.java:1002)
          at org.hibernate.loader.Loader.doQuery(Loader.java:960)
          at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:351)
          at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:321)
          at org.hibernate.loader.Loader.loadEntity(Loader.java:2379)
          at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:64)
          at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:54)
          at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:4289)
          at org.hibernate.event.internal.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:597)
          at org.hibernate.event.internal.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:565)
          at org.hibernate.event.internal.DefaultLoadEventListener.load(DefaultLoadEventListener.java:226)
          at org.hibernate.event.internal.DefaultLoadEventListener.doOnLoad(DefaultLoadEventListener.java:122)
          at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:93)
          ...
  

Source Code Example/Excerpt

@Entity
public class Employee {
        @Id
        private String name;

        @OneToMany(mappedBy = "taskParticipantPK.employee", cascade = CascadeType.ALL, orphanRemoval = true)
        private List<TaskParticipant> taskParticipants;
}

@Entity
public class Task {
        @Id
        private long id;

        @OneToMany(mappedBy = "taskParticipantPK.task", cascade=CascadeType.ALL)
        private List <TaskParticipant> taskParticipants;
}

@Entity
public class TaskParticipant {
        @EmbeddedId
        private TaskParticipantPK taskParticipantPK = new TaskParticipantPK();
}

@Embeddable
@Table(name = "TaskParticipant")
public class TaskParticipantPK implements Serializable {
        private static final long serialVersionUID = 1;

        @ManyToOne(fetch = FetchType.LAZY)
        @JoinColumn(name = "employee")
        private Employee employee;

        @ManyToOne(fetch = FetchType.LAZY)
        @JoinColumn(name = "task")
        private Task task;
}