org.hibernate.MappingException: Repeated column in mapping for entity: com.company.product.datamodel.Cdo column: session_id (should be mapped with insert="false" update="false")
   at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:682)
   at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:704)
   ...

CREATE TABLE `session` (
  `id` int(11) NOT NULL,
  `name` varchar(120) DEFAULT NULL,
  `ref_date` date DEFAULT NULL,
  PRIMARY KEY (`id`)
)

CREATE TABLE `currency` (
  `session_id` int(11) NOT NULL,
  `id` int(11) NOT NULL,
  `code` char(3) DEFAULT NULL,
  `rate2eur` decimal(24,12) DEFAULT NULL,
  PRIMARY KEY (`session_id`,`id`)
)

CREATE TABLE `instrument` (
  `session_id` int(11) NOT NULL,
  `id` int(11) NOT NULL,
  `name` varchar(45) NOT NULL,
  `currency_id` int(11) NOT NULL,
  PRIMARY KEY (`session_id`,`id`)
)

@Entity
@Table(name="session")
public class Session {
   @javax.persistence.Id
   private int id;
   @Column(name="name")
   private String name;
   @Column(name="ref_date")
   private Date referenceDate;
   @OneToMany(mappedBy="session")
   private List<Instrument> instruments;
   
   ...
}

@Embeddable
public class DbId implements Serializable {
   private static final long serialVersionUID = 1L;
   
   @Column(name="id")
   private int id;
   @Column(name="session_id")
   private int sessionId;

   ...
   
   @Override
   public boolean equals(Object obj) {
      if(!(obj instanceof DbId))
         return false;
      DbId idObj = (DbId) obj;
      return id == idObj.getId() && sessionId == idObj.getSessionId();
   }
   
   @Override
   public int hashCode() {
      return id * 31 + sessionId;
   }
}

@Entity
@Table(name="currency")
public class Currency {
   @EmbeddedId
   @AttributeOverrides( {
      @AttributeOverride(name="id", column = @Column(name="id") ),
      @AttributeOverride(name="sessionId", column = @Column(name="session_id") )
   } )
   private DbId id;
   
   @Column(name="code")
   private String name;
   
   @Column(name="rate2eur")
   private Double rate2Eur;
   
   ...
}

@Entity
@Table(name="instrument")
public class Instrument {
   @EmbeddedId
   @AttributeOverrides( {
      @AttributeOverride(name="id", column = @Column(name="id") ),
      @AttributeOverride(name="sessionId", column = @Column(name="session_id") )
   } )
   private DbId id;
   @Column(name="name")
   private String name;
   @ManyToOne
   @JoinColumn(name="session_id", insertable=false, updatable=false)
   private Session session;
   @ManyToOne
   @JoinColumns({
      @JoinColumn(name="currency_id", referencedColumnName="id"),
      @JoinColumn(name="session_id", referencedColumnName="session_id")
   })
   private Currency currency;

   ...
}