problem with ClassCastException

[navdeep thakur]

Hi guys,
I am very new to Hibernate and trying to learn it. I have developed a small application which will fetch results from the database(Postgres) with the specified "where" condition.
But I am getting an Exception:
java.lang.ClassCastException: [Ljava.lang.Object;
at com.myapps.GetData.main(GetData.java:46)


My code is given below:
1) For Bean Class

  package com.myapps;
 
public class UserBean 
{
private String firstname;
private String password;
private String emailaddress;
private Long id;
 
public Long getId() {
return id;
}
 
public void setId(Long id) {
this.id = id;
}

public String getEmailaddress() {
return emailaddress;
}
 

public void setEmailaddress(String emailaddress) {
this.emailaddress = emailaddress;
}
 

public String getFirstname() {
return firstname;
}
 

public void setFirstname(String firstname) {
this.firstname = firstname;
}
 

public String getPassword() {
return password;
}
 

public void setPassword(String password) {
this.password = password;
}
 
}
  

2) Code for main class:

  package com.myapps;
 
import java.util.Iterator;
import java.util.List;
 
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
 
public class GetData 
{
/**
 * @param args
 */
public static void main(String[] args)
{
Session session=null;
//Query query;
List list;
Query query;
String str_query;
String name;
String password;
try
{System.out.println("before Session Factory");
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
        session =sessionFactory.openSession();
        System.out.println("After Session Factory");
        //org.hibernate.Transaction tx = session.beginTransaction();
        
       str_query="Select user.id, user.firstname, user.password, user.emailaddress from UserBean user"+" where user.firstname= 'navi'";
        
       //str_query=" from UserBean user";
        //str_query="from userinfo as useri where useri.firstname=navi"; 
        query=session.createQuery(str_query);         
         System.out.println("After Query");
         list = query.list();
         System.out.println("Query to List");
       // Iterator it=list.iterator();
         for(Iterator it=list.iterator();it.hasNext() :wink: 
        
        //while(it.hasNext())
         {
         System.out.println("IN FOR LOOP *****************************"+ list.get(0));
         UserBean userB=(UserBean)it.next();
         //Object[] tupple=it.hasNext();
         System.out.println("user name is :"+ userB.getFirstname());
         System.out.println("user name is :"+ userB.getPassword());
         }
         
         /*for(Iterator  iterator = list.iterator(); iterator.hasNext() :wink: 
         { System.out.println("In for Loop");
         UserBean user = (UserBean) iterator.next();
         cName = user.getName();
         cPassword = user.getPassword();
         System.out.println("User Name     : " + cName );
         System.out.println("User Password : " + cPassword);
         }
        */
         
}
catch(Exception e)
{
e.printStackTrace();
}
 
}
 
}
  

Please please help me out....

[krishna bulusu]

See, in this case you will get an array of Object.

for(Iterator it=list.iterator();it.hasNext(){
Object[] user = (Object[])it.nextElement();
}

Navigate through the array for the elements.
Hope you understand it.

[navdeep thakur]

Hi Krishna,
I had tried your recommended way, but Iterator doesn't have nextElement() method, So can you please elaborate it.

Thanks

[navdeep thakur]

I have one query, as it is confusing me from today.

If i need to retrieve a record from the database through select statement, I use object of Class Query.. right.
So which import do i use either

import org.hibernate.Query or
import javax.persistence.Query

First clear me this think, as i noticed today.
Thanks

[Mr. C Lamont Gilbert]

You are dealing with hibernate so use the hibernate class.

The easiest way to figure out the problem is to stop casting, and use Object class. Then open your debugger and see what the type really is.

Exactly where are you getting the exception?
[ July 30, 2007: Message edited by: Mr. C Lamont Gilbert ]

[navdeep thakur]

Hello Mr. C Lamont Gilbert,
Actually I am getting ClassCastException at the following point:

UserBean user = (UserBean) iterator.next();

Where UserBean is my bean class where i have my getter and setter methods.
The code for UserBean class is given above. Please have a look.

Thanks

[Ulf Dittmer]

If you have a query like "Select user.id, user.firstname, user.password, user.emailaddress from UserBean where ...", then you will get back an Object[], not a UserBean, as was pointed out above.

If you want an array of UserBean objects, change the query to something like "from UserBean where ..." (without the SELECT part).

If you want one particular UserBean, you can use "(UserBean) sess.load(UserBean.class, user.id)", assuming user.id is the primary key of UserBean.

Liastly, the name of the method for getting the next element of an Iterator is not netxElement, as you found out, but can easily be determined by looking at the javadocs.