@Entity
public class A {
  @Id
  @Column(name = "OBJECT_ID")
  private String objectId;
  
  @OneToOne(mappedBy = "a")
  private B b;
  
  ...
}

@Entity
public class B {
  @Id
  @Column(name = "OBJECT_ID")
  private String objectId;
  
  @OneToOne
  @JoinColumns({
      @JoinColumn(name = "ID", referencedColumnName = "ID", insertable = false, updatable = false),
      @JoinColumn(name = "ID_NUMBER", referencedColumnName = "ID_NUMBER", insertable = false, updatable = false)
  })
  private A a;
  
  ...
}