Hi to all,
i am using from clause but it is not working ,i get null value , select query works fine.

When i use from i get following message
"

Hibernate: select address0_.id as col_0_0_ from ADDRESS address0_
null
"
this is my code
plz tell me where is error

package hiber.scr;
import java.util.Iterator;
import org.hibernate.*;
import org.hibernate.cfg.*;

import java.util.*;
public class FirstExample {



public static void main(String[] args) {
Session session = null;

try{
// This step will read hibernate.cfg.xml and prepare hibernate for use
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
session =sessionFactory.openSession();

// String SQL_QUERY ="Select insurance.addressId,insurance.street," +
// "insurance.city,insurance.state from Address insurance";
//Using from Clause
String SQL_QUERY ="from Address add";
Query query = session.createQuery(SQL_QUERY);
for(Iterator it=query.iterate();it.hasNext();){
Address add=(Address)it.next();

System.out.println("ID: " +add.getAddressId() );

}

session.close();
}catch(Exception e){
System.out.println(e.getMessage());
}finally{
}

}
}
------------------------------------------------------------------------------------------

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="hiber.scr.Address" table="ADDRESS">
<meta attribute="class-description">This class contains the student's address
details.</meta>
<id name="addressId" type="long" column="id">
<generator class="identity" />
</id>
<property name="street" column="street"
/>
<property name="city" column="city"
/>
<property name="state" column="state"
/>
<property name="zipcode" column="zipcode"
/>
</class>
</hibernate-mapping>
-------------------------------------------------------------------------

package hiber.scr;

public class Address {
private long addressId;
private String street;
private String city;
private String state;
private String zipcode;

public Address(String street, String city, String state, String zipcode) {
this.street = street;
this.city = city;
this.state = state;
this.zipcode = zipcode;

}

public long getAddressId() {
return addressId;
}

public void setAddressId(long addressId) {
this.addressId = addressId;
}

public String getStreet() {
return street;
}

public void setStreet(String street) {
this.street = street;
}

public String getCity() {
return city;
}

public void setCity(String city) {
this.city = city;
}

public String getState() {
return state;
}

public void setState(String state) {
this.state = state;
}

public String getZipcode() {
return zipcode;
}

public void setZipcode(String zipcode) {
this.zipcode = zipcode;
}
}
---------------------------------------------

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">
com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">
jdbc:mysql://localhost/hibernate</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<!-- Mapping files -->
<mapping resource="contact.hbm.xml" />
<mapping resource="student.hbm.xml" />
<mapping resource="Address.hbm.xml" />
</session-factory>
</hibernate-configuration>


-------------------------------------------------------------------------------------
thanks

Try adding a no-arg constructor to the Address class.

thanks,
it works but can u plz explain why i have to use a zero constructor

Hibernate requires all persistent classes to have a no-arg constructor, which is what it calls to instantiate the class.