@Entity
@Table(name = "table1", uniqueConstraints = @UniqueConstraint(columnNames = "table1ID"))
public class Table1  implements java.io.Serializable {

   /**
    * Serial Id of the class.
    */
   private static final long serialVersionUID = 4098136300929982619L;

   @Id
   @GeneratedValue(strategy = IDENTITY)
   @Column(name = "table1ID", unique = true, nullable = false)
   private Long table1ID =  DatabaseConstants.INVALID_VALUE;
      
   @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "table2")
   private Set<Table2> table2 = new HashSet<table2>(0);
   
}

@Entity
@Table(name = "table2", uniqueConstraints = @UniqueConstraint(columnNames = "table2ID"))
public class Table2   implements java.io.Serializable {
   
   /**
    * Serial Id of the class.
    */
   private static final long serialVersionUID = 5395459647729458145L;

   @Id
   @GeneratedValue(strategy = IDENTITY)
   @Column(name = "table2ID", unique = true, nullable = false)
   private Long table2ID =  DatabaseConstants.INVALID_VALUE;

   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumn(name = "table1ID", nullable = false)
   private Table1 table1;
   
   @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "table3")
   private Set<Table3> table3 = new HashSet<table3>(0);
}

@Entity
@Table(name = "table3", uniqueConstraints = @UniqueConstraint(columnNames = "table3ID"))
public class Table3   implements java.io.Serializable {
   
   /**
    * Serial Id of the class.
    */
   private static final long serialVersionUID = 5395459647729458145L;

   @Id
   @GeneratedValue(strategy = IDENTITY)
   @Column(name = "table3ID", unique = true, nullable = false)
   private Long table3ID =  DatabaseConstants.INVALID_VALUE;

   @ManyToOne(fetch = FetchType.LAZY)
   @JoinColumn(name = "table2ID", nullable = false)
   private Table2 table2;
}



insertTable2(Table2 table2){
         this.userTxn.begin();
         this.entityManager.persist(table2);
         this.entityManager.flush();
         this.userTxn.commit();
}