Hibernate Many-To-One Unidirectional Mapping

public class User {
   private int id;
   private String name;
   private Group group;
       
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    @ManyToOne
    public Group getGroup() {
        return group;
    }
    public void setGroup(Group group) {
        this.group = group;
    }
    
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

public class Group {
    private int id;
    private String name;

    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    
    public void setId(int id) {
        this.id = id;
    }
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }    
}

<class name="User" table ="U_User">
   <id name="id"></id>
    <property name="name"></property>
    <!-- column="xx" name column as xx in DB -->
    <many-to-one name="group" column="groupId" >
   </many-to-one>
</class>


<hibernate-mapping package="com.hibernate.model">
<class name="Group" table="T_Group">
   <id name="id"></id>
    <property name="name"></property>
</class>