lazy="false"查询时并没懒加载，怎么回事？

Userdb.hbm.xml
<hibernate-mapping>
    <class name="com.zjm.ssh2.pojo.Userdb" table="userdb">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <many-to-one name="codedb" class="com.zjm.ssh2.pojo.Codedb" fetch="select">
            <column name="sexid" not-null="true" />
        </many-to-one>
        <property name="username" type="java.lang.String">
            <column name="username" length="20" not-null="true" />
        </property>
        <property name="password" type="java.lang.String">
            <column name="password" length="20" not-null="true" />
        </property>
        <set name="userRoles" inverse="false" lazy="false">
            <key>
                <column name="userid" />
            </key>
            <one-to-many class="com.zjm.ssh2.pojo.UserRole" />
        </set>
        <set name="articles" inverse="true">
            <key>
                <column name="userid" />
            </key>
            <one-to-many class="com.zjm.ssh2.pojo.Article" />
        </set>
    </class>
</hibernate-mapping>UserRole.hbm.xml
<hibernate-mapping>
    <class name="com.zjm.ssh2.pojo.UserRole" table="user_role">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <many-to-one name="roles" class="com.zjm.ssh2.pojo.Roles" fetch="select">
            <column name="roleid" />
        </many-to-one>
        <many-to-one name="userdb" class="com.zjm.ssh2.pojo.Userdb" fetch="select">
            <column name="userid" />
        </many-to-one>
    </class>
</hibernate-mapping>Roles.hbm.xml
<hibernate-mapping>
    <class name="com.zjm.ssh2.pojo.Roles" table="roles">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="rolename" type="java.lang.String">
            <column name="rolename" length="30" />
        </property>
        <property name="re" type="java.lang.String">
            <column name="re" length="100" />
        </property>
        <set name="userRoles" inverse="false">
            <key>
                <column name="roleid" />
            </key>
            <one-to-many class="com.zjm.ssh2.pojo.UserRole" />
        </set>
    </class>
</hibernate-mapping>
Userdb.hbm.xml配置里<set name="userRoles"设置成懒加载
查询userdb时也应该执行查询userrole才对，可是只查了userdb，没查userrole，怎么回事？