Puhong You ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *commented* on HHH-15453 ( https://hibernate.atlassian.net/browse/HHH-15453?atlOrigin=eyJpIjoiY2MyMW... ) Re: java.lang.NullPointerException: Cannot invoke "org.hibernate.engine.spi.EntityEntry.getEntityKey()" because "ownerEntry" is null ( https://hibernate.atlassian.net/browse/HHH-15453?atlOrigin=eyJpIjoiY2MyMW... ) Hi, Andrea, I oversimplified the test case when I initially reported this bug. I apologize for my mistake. The missing piece is the Agency object. The object hierarchy is like this: each Agency can have 0 or more Users, and each User must belong to an Agency and each user can have 0 or more roles. Here is the Agency table: AGENCY table: Columns: AGENCY_ID integer not null primary key, AGENCY_NAME varchar(256) not null, Rows: (100, 'Test Agency'); USER table (add the AGENCY_ID column): Columns: USER_ID integer not null primary key, USER_NAME varchar(256) not null, AGENCY_ID integer not null, Rows: (1, 'Ann', 100); (2, 'Bob', 100); Here is the Agency entity bean: @Entity@Table(name = "AGENCY" , schema = "TEST" ) public class Agency { private Integer agencyId = null ; private String agencyName = null ; private Set<User> users; @Id @Column(name = "AGENCY_ID" ) public Integer getAgencyId() { return agencyId; } public void setAgencyId( Integer roleId) { this.agencyId = roleId; } @Column(name = "AGENCY_NAME" ) public String getAgencyName() { return agencyName; } public void setAgencyName( String roleName) { this.agencyName = roleName; } @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, mappedBy = "agency" ) @Fetch(FetchMode.SELECT) public Set<User> getUsers() { return users; } public void setUsers(Set<User> users) { this.users = users; } @Override public boolean equals( Object o) { if ( this == o) { return true ; } if (o == null || getClass() != o.getClass()) { return false ; } Agency that = (Agency) o; return Objects.equals(agencyId, that.agencyId) && Objects.equals(agencyName, that.agencyName); } @Override public int hashCode() { return Objects.hash(agencyId, agencyName); } Here are the updated User entity bean: @Entity@Table(name = "USER" , schema = "TEST" ) public class User { private Integer userId = null ; private String userName = null ; private Agency agency = null ; private Set<Role> roles = null ; @Id @Column(name = "CRIS_USER_ID" ) public Integer getUserId() { return userId; } public void setUserId( Integer userId) { this.userId = userId; } @Column(name = "IDP_USER_ID" ) public String getUserName() { return userName; } public void setUserName( String userName) { this.userName = userName; } @ManyToOne @JoinColumn(name = "AGENCY_ID" ) public Agency getAgency() { return agency; } public void setAgency(Agency agency) { this.agency = agency; } @ManyToMany(cascade = CascadeType.PERSIST, fetch = FetchType.EAGER) @JoinTable( name = "UM_USER_ROLE" , joinColumns = @JoinColumn(name = "CRIS_USER_ID" ), inverseJoinColumns = @JoinColumn(name = "ROLE_ID" )) @Fetch(FetchMode.SUBSELECT) public Set<Role> getRoles() { return roles; } public void setRoles(Set<Role> roles) { this.roles = roles; } I am able to reproduce the reported java.lang.NullPointerException. ( https://hibernate.atlassian.net/browse/HHH-15453#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15453#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#100205- sha1:6417f3f )