Hibernate version:3.0

My database have this relationships:
A table named "Item". The primary key is (cod_empresa, cod_item)
A table named "Estrutura". The primary key is
(cod_empresa, cod_item_pai, cod_item_filho)
I have two foreign keys for "estrutura":
estrutura (cod_empresa, cod_item_pai) -> item (cod_empresa, cod_item)
estrutura (cod_empresa, cod_item_compon) -> item (cod_empresa, cod_item)

This means that an "Item" has a collection os "Estrutura"

Item ----------> estrutura
1.. ..N

I made these mapping for both classes:

Item map:
<hibernate-mapping>
<class name="imb.fabrica.database.Item" table="item" mutable="false">
<composite-id>
<key-property name="codEmpresa" column="cod_empresa"/>
<key-property name="codItem" column="cod_item"/>
</composite-id>

<set name="estrutura" table="estrutura">
<key>
<column name="cod_empresa"/>
<column name="cod_item_pai"/>
</key>
<one-to-many class="imb.fabrica.database.Estrutura"/>
</set>
</class>
</hibernate-mapping>


Estrutura map:

<hibernate-mapping>
<class name="imb.fabrica.database.Estrutura" table="estrutura" mutable="false">
<composite-id>
<key-property name="codEmpresa" column="cod_empresa"/>
<key-property name="codItemPai" column="cod_item_pai"/>
<key-property name="codItemCompon" column="cod_item_compon"/>
</composite-id>

<many-to-one name="itemPai" class="imb.fabrica.database.Item" insert="false" update="false">
<column name="cod_empresa"/>
<column name="cod_item_pai"/>
</many-to-one>

<many-to-one name="itemFilho" class="imb.fabrica.database.Item" insert="false" update="false">
<column name="cod_empresa"/>
<column name="cod_item_compon"/>
</many-to-one>

</class>

</hibernate-mapping>


when I try to execute the following code,
the iterator doenst print any son! The method getCodItemCompon()
returns an empty collection. Why???
:
Item i = new Item("01", "7210971992");

i = (Item) session.get(Item.class, i);

for (Estrutura e: i.getEstrutura()){
System.out.println("son: " + e.getCodItemCompon());
}

Item.java:

package imb.fabrica.database;

import java.io.Serializable;
import java.util.Collection;
import java.util.HashSet;


public class Item implements Serializable{
private String codEmpresa;
private String codItem;

private Collection<Estrutura> estrutura = new HashSet<Estrutura>();


public Item(){

}

public Item(String codEmpresa, String codItem){
super();
this.codEmpresa = codEmpresa;
this.codItem = codItem;
}


public String getCodEmpresa() {
return codEmpresa;
}

public void setCodEmpresa(String codEmpresa) {
this.codEmpresa = codEmpresa;
}

public String getCodItem() {
return codItem;
}

public void setCodItem(String codItem) {
this.codItem = codItem;
}

public Collection<Estrutura> getEstrutura() {
return estrutura;
}

public void setEstrutura(Collection<Estrutura> estrutura) {
this.estrutura = estrutura;
}
}

Estrutura.java:

package imb.fabrica.database;

import java.io.Serializable;


public class Estrutura implements Serializable{

private String codEmpresa;
private String codItemPai;
private String codItemCompon;

private Item itemPai;
private Item itemFilho;
private Double quantidade;

public Estrutura(){

}

public Item getItemFilho() {
return itemFilho;
}

public void setItemFilho(Item itemFilho) {
this.itemFilho = itemFilho;
}

public Item getItemPai() {
return itemPai;
}

public void setItemPai(Item itemPai) {
this.itemPai = itemPai;
}

public Double getQuantidade() {
return quantidade;
}

public void setQuantidade(Double quantidade) {
this.quantidade = quantidade;
}

public String getCodEmpresa() {
return codEmpresa;
}

public void setCodEmpresa(String codEmpresa) {
this.codEmpresa = codEmpresa;
}

public String getCodItemCompon() {
return codItemCompon;
}

public void setCodItemCompon(String codItemCompon) {
this.codItemCompon = codItemCompon;
}

public String getCodItemPai() {
return codItemPai;
}

public void setCodItemPai(String codItemPai) {
this.codItemPai = codItemPai;
}
}


Debug level Hibernate log excerpt:
19:28:54,828 DEBUG SQL:292 - select item0_.cod_empresa as cod1_0_, item0_.cod_item as cod2_0_ from item item0_ where item0_.cod_empresa=? and item0_.cod_item=?
Hibernate: select item0_.cod_empresa as cod1_0_, item0_.cod_item as cod2_0_ from item item0_ where item0_.cod_empresa=? and item0_.cod_item=?
19:28:54,828 DEBUG AbstractBatcher:343 - preparing statement
19:28:54,843 DEBUG StringType:59 - binding '01' to parameter: 1
19:28:54,843 DEBUG StringType:59 - binding '7210971992' to parameter: 2
19:28:54,843 DEBUG AbstractBatcher:274 - about to open ResultSet (open ResultSets: 0, globally: 0)
19:28:54,843 DEBUG AbstractBatcher:281 - about to close ResultSet (open ResultSets: 1, globally: 1)
19:28:54,859 DEBUG AbstractBatcher:266 - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
19:28:54,859 DEBUG AbstractBatcher:363 - closing statement
19:28:54,890 DEBUG AbstractBatcher:258 - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
19:28:54,890 DEBUG SQL:292 - select estrutura0_.cod_empresa as cod1___, estrutura0_.cod_item_pai as cod2___, estrutura0_.cod_item_compon as cod3___, estrutura0_.cod_empresa as cod1_0_, estrutura0_.cod_item_pai as cod2_0_, estrutura0_.cod_item_compon as cod3_0_, estrutura0_.cod_empresa as cod1_37_0_, estrutura0_.cod_item_pai as cod2_37_0_, estrutura0_.cod_item_compon as cod3_37_0_ from estrutura estrutura0_ where estrutura0_.cod_empresa=? and estrutura0_.cod_item_pai=?
Hibernate: select estrutura0_.cod_empresa as cod1___, estrutura0_.cod_item_pai as cod2___, estrutura0_.cod_item_compon as cod3___, estrutura0_.cod_empresa as cod1_0_, estrutura0_.cod_item_pai as cod2_0_, estrutura0_.cod_item_compon as cod3_0_, estrutura0_.cod_empresa as cod1_37_0_, estrutura0_.cod_item_pai as cod2_37_0_, estrutura0_.cod_item_compon as cod3_37_0_ from estrutura estrutura0_ where estrutura0_.cod_empresa=? and estrutura0_.cod_item_pai=?
19:28:54,890 DEBUG AbstractBatcher:343 - preparing statement
19:28:54,890 DEBUG StringType:59 - binding '01' to parameter: 1
19:28:54,890 DEBUG StringType:59 - binding '7210971992' to parameter: 2
19:28:54,890 DEBUG AbstractBatcher:274 - about to open ResultSet (open ResultSets: 0, globally: 0)
19:28:54,890 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,890 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,906 DEBUG StringType:86 - returning '500017 ' as column: cod3_0_
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,906 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,906 DEBUG StringType:86 - returning '500017 ' as column: cod3_37_0_
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,906 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,906 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,906 DEBUG StringType:86 - returning '500017 ' as column: cod3___
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,906 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,906 DEBUG StringType:86 - returning '500115 ' as column: cod3_0_
19:28:54,906 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,921 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,921 DEBUG StringType:86 - returning '500115 ' as column: cod3_37_0_
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,921 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,921 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,921 DEBUG StringType:86 - returning '500115 ' as column: cod3___
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,921 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,921 DEBUG StringType:86 - returning '500118 ' as column: cod3_0_
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,921 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,921 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,937 DEBUG StringType:86 - returning '500118 ' as column: cod3_37_0_
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,937 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,937 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,937 DEBUG StringType:86 - returning '500118 ' as column: cod3___
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,937 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,937 DEBUG StringType:86 - returning '503379 ' as column: cod3_0_
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,937 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,937 DEBUG StringType:86 - returning '503379 ' as column: cod3_37_0_
19:28:54,937 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,937 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,953 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,953 DEBUG StringType:86 - returning '503379 ' as column: cod3___
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,953 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,953 DEBUG StringType:86 - returning '503432 ' as column: cod3_0_
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,953 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,953 DEBUG StringType:86 - returning '503432 ' as column: cod3_37_0_
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,953 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,953 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,953 DEBUG StringType:86 - returning '503432 ' as column: cod3___
19:28:54,953 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,968 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,968 DEBUG StringType:86 - returning '503548 ' as column: cod3_0_
19:28:54,968 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,984 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:54,984 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,984 DEBUG StringType:86 - returning '503548 ' as column: cod3_37_0_
19:28:54,984 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,984 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,984 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:54,984 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:54,984 DEBUG StringType:86 - returning '503548 ' as column: cod3___
19:28:54,984 DEBUG StringType:86 - returning '01' as column: cod1_0_
19:28:54,984 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_0_
19:28:54,984 DEBUG StringType:86 - returning '7210971992T ' as column: cod3_0_
19:28:54,984 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:54,984 DEBUG StringType:86 - returning '7210971992 ' as column: cod2_37_0_
19:28:55,000 DEBUG StringType:86 - returning '01' as column: cod1_37_0_
19:28:55,000 DEBUG StringType:86 - returning '7210971992T ' as column: cod3_37_0_
19:28:55,000 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:55,000 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:55,000 DEBUG StringType:86 - returning '01' as column: cod1___
19:28:55,000 DEBUG StringType:86 - returning '7210971992 ' as column: cod2___
19:28:55,000 DEBUG StringType:86 - returning '7210971992T ' as column: cod3___
19:28:55,000 DEBUG AbstractBatcher:281 - about to close ResultSet (open ResultSets: 1, globally: 1)
19:28:55,000 DEBUG AbstractBatcher:266 - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
19:28:55,000 DEBUG AbstractBatcher:363 - closing statement