public class Students{
    private Integer id;
    private String stId;
    private String stName;
    private Classes class;    ...
}public class Classes {
    private Integer id;
    private String classId;
    private String className;    ...
}<hibernate-mapping package="">
    <class name="Students" table="STUDENTS" >
        <cache usage="nonstrict-read-write"/>
        <id name="id" column="ID">
            <generator class="native"/>
        </id>
        <property name="stId" column="STID"/>
        <property name="stName" column="STNAME"/>
        <many-to-one name="class" column="C_ID" class="Classes" not-null="true"/>
    </class>
</hibernate-mapping><hibernate-mapping package="">
    <class name="Classes" table="CLASSES" >
        <cache usage="nonstrict-read-write"/>
        <id name="id" column="ID">
            <generator class="native"/>
        </id>
        <property name="classId" column="CLASSID"/>
        <property name="className" column="CLASSNAME"/>
    </class>
</hibernate-mapping>