// Package.hbm.xml
<hibernate-mapping>
  <class catalog="p2p" name="Entity.Package" table="package">
    <composite-id class="Entity.PackageId" name="id">
      <key-property name="id" type="int">
        <column name="id"/>
      </key-property>
      <key-property name="idProduct" type="int">
        <column name="idProduct"/>
      </key-property>
    </composite-id>
    <many-to-one class="Entity.User" fetch="select" name="usuer">
      <column length="50" name="email" not-null="true"/>
    </many-to-one>
    <many-to-one class="Entity.Produc" fetch="select" insert="false" name="product" update="false">
      <column name="idProduct" not-null="true"/>
    </many-to-one>
    <property name="quantity" type="int">
      <column name="quantity" not-null="true"/>
    </property>
    <property name="mode" type="char">
      <column length="1" name="mode not-null="true"/>
    </property>
    <property name="unity" type="string">
      <column length="25" name="unity" not-null="true"/>
    </property>
    <property name="description" type="string">
      <column length="150" name="description" not-null="true"/>
    </property>
  </class>
</hibernate-mapping>

// Product.hbm.xml
<hibernate-mapping>
  <class catalog="p2p" name="Entity.Product" table="product">
    <id name="id" type="int">
      <column name="id"/>
      <generator class="assigned"/>
    </id>
    <property name="nome" type="string">
      <column length="150" name="nome" not-null="true"/>
    </property>
    <set inverse="true" name="packages" cascade="save-update, delete">
      <key>
        <column name="idProduct" not-null="true"/>
      </key>
      <one-to-many class="Entity.Package"/>
    </set>
  </class>
</hibernate-mapping>

//Product.hbm.xml
<hibernate-mapping>
  <class catalog="p2p" name="Entity.Product" table="product">
    <id name="id" type="int">
      <column name="id"/>
      <generator class="assigned"/>
    </id>
    <property name="nome" type="string">
      <column length="150" name="nome" not-null="true"/>
    </property>
    <set inverse="true" name="packages" cascade="save-update, delete">
      <key>
        <column name="idProduct" not-null="true"/>
      </key>
      <one-to-many class="Entity.Package"/>
    </set>
  </class>
</hibernate-mapping>