org.hibernate.MappingException: Following superclasses referenced in extends not found: null

[Shubham Semwal]

Employee.java

public class Employee {

	private int id;
	private String name;

//setter/getters
}
	

RegularEmployee

public class RegularEmployee extends Employee {

	private float salary;
	private int bonus;

//getter/setters
}
	

ContractEmployee

public class ContractEmployee extends Employee {

	private float perHourPay;
	private String contractDuration;
	
	//getter/setters
	}

StoreData

public class StoreData {

	public static void main(String[] args) {
		
		Session session = new Configuration().configure("hibernate.cfg.xml").buildSessionFactory().openSession();
		
		Transaction t = session.beginTransaction();
		
		Employee e = new Employee();
			e.setName("Shubham");
			
		RegularEmployee er = new RegularEmployee();
			er.setName("Akash");
			er.setBonus(10000);
			er.setSalary(100000);
			
		ContractEmployee ec = new ContractEmployee();
			ec.setName("Kedar");
			ec.setContractDuration("1 year");
			ec.setPerHourPay(10000);
			
		session.persist(e);
		session.persist(er);
		session.persist(ec);
		
		t.commit();
		session.close();
		System.out.println("Success");
	}	
}

employee.hbm.xml

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-mapping PUBLIC  
          "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
          "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
  
<hibernate-mapping>
	<class name="com.hibernateinheritancemapping.tableperhierarchy.Employee" table="EmpInheritanceMappingSingleTable" discriminator-value="emp">
		<id name="id">
			<generator class="increment"></generator>
		</id>
		
		<discriminator column="EmpType" type="String" ></discriminator>
		<property name="name"></property>
	</class>
	
	<subclass name="com.hibernateinheritancemapping.tableperhierarchy.RegularEmployee" discriminator-value="empReg">
		<property name="salary"></property>
		<property name="bonus"></property>
	</subclass>
	
	<subclass name="com.hibernateinheritancemapping.tableperhierarchy.ContractEmployee" discriminator-value="empCont">
		<property name="perHourPay"></property>
		<property name="contractDuration"></property>
	</subclass>

</hibernate-mapping>

hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-configuration PUBLIC  
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"  
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">  
  
<hibernate-configuration>  
  
    <session-factory>  
        <property name="hbm2ddl.auto">update</property>  
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>  
        <property name="connection.url">jdbc:mysql://localhost/HibernateDB</property>  
        <property name="connection.username">root</property>  
        <property name="connection.password">root</property>  
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>  
    <mapping resource="employee.hbm.xml"/>  
    </session-factory>  
  
</hibernate-configuration> 

Error : Exception in thread "main" org.hibernate.MappingException: Following superclasses referenced in extends not found: null
at org.hibernate.cfg.Configuration.processExtendsQueue(Configuration.java:1200)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1119)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1283)
at com.hibernateinheritancemapping.tableperhierarchy.StoreData.main(StoreData.java:11)


Please advise.
Thanks

[Ramya R Subramanian]

I assume you are trying to work on table per class hierarchy . In employee.hbm.xml  close the <class> tag at the end, before the tag </hibernate-mapping>.

</class>
</hibernate-mapping>

and the type is "string" and not "String"

<discriminator column="EmpType" type="string" ></discriminator>

like here below

<?xml version='1.0' encoding='UTF-8'?>  
<!DOCTYPE hibernate-mapping PUBLIC  
          "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 
          "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
   
<hibernate-mapping>
    <class name="com.hibernateinheritancemapping.tableperhierarchy.Employee" table="EmpInheritanceMappingSingleTable" discriminator-value="emp">
        <id name="id">
            <generator class="increment"></generator>
        </id>
         
        <discriminator column="EmpType" type="string" ></discriminator>
        <property name="name"></property>

     
    <subclass name="com.hibernateinheritancemapping.tableperhierarchy.RegularEmployee" discriminator-value="empReg">
        <property name="salary"></property>
        <property name="bonus"></property>
    </subclass>
     
    <subclass name="com.hibernateinheritancemapping.tableperhierarchy.ContractEmployee" discriminator-value="empCont">
        <property name="perHourPay"></property>
        <property name="contractDuration"></property>
    </subclass>
    </class> 
</hibernate-mapping>

[Shubham Semwal]

Thanks a lot Ramya.
Its working

[Roel De Nijs]

Shubham Semwal wrote:Thanks a lot Ramya.

That definitely deserves a cow!