Nullpointer Exception while calling session.get() method in Hibernate

Question

I am new to hibernate.When i'm trying to call session.get() method then Nullpointer Exception is occurring.How can i fix it

My pojo class:-

package test;
import java.util.*;

public class user1 implements java.io.Serializable{

private int id;
private String name;
private String department;
private String password;

public user1() {}

public user1(int id,String name, String department, String password) {
      this.id = id;
      this.name = name;
      this.department = department;
      this.password = password;
}

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;
}

public String getDepartment() {
    return department;
}

public void setDepartment(String department) {
    this.department = department;
}

public String getPassword() {
    return password;
}

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

}

My user1.hbm.xml file:

<?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="test.user1" table="users">

<id name="id" column="id" type="int">
</id>
<property name="name" column="name" type="string"/>
<property name="department" column="department" type="string"/>
<property name="password" column="password" type="string"/>

</class>
</hibernate-mapping>

I am calling session.get(user1.class,id) method in my updateUser() function. Nullpointer exception is thrown at runtime.

public class user2 {

private static SessionFactory factory;
public static void main(String [] args){

    try{
        factory = new Configuration().configure().buildSessionFactory();

    }
    catch (Throwable ex) { 
        System.err.println("SessionFactory object could not be created"+ex);
        throw new ExceptionInInitializerError(ex); 
    }

    user2 User = new user2();
    //User.addUser(3,"cc","cse","cc");
    //User.showUser();
    User.updateUser(Integer.valueOf(3),"dd","cse","dd");

}

public void addUser(int id,String name,String department,String password){
    Session session = factory.openSession();
    Transaction t = null;
    try{
        t = session.beginTransaction();
        user1 User1 = new user1(id,name,department,password);
        session.save(User1);
        t.commit();
    }
    catch (HibernateException e) {
         if (t!=null) t.rollback();
            e.printStackTrace(); 
    }
    finally {
         session.close(); 
    }
}



public void updateUser(Integer id,String name,String department,String password){
    Session session = factory.openSession();
    Transaction t = null;
    try{
        user1 user = (user1)session.get(user1.class,id);

        user.setName(name);
        user.setDepartment(department);
        user.setPassword(password);
        session.update(user);
        t.commit();
    }
    catch (HibernateException e) {
         if (t!=null) t.rollback();
            e.printStackTrace(); 
    }
    finally {
         session.close(); 
    }

}
}

}

error shown in console:->Exception in thread "main" java.lang.NullPointerException at test.user2.updateUser(user2.java:87) at test.user2.main(user2.java:30) — user3921678, Aug 29 '14 at 07:03

score 0 · Answer 1 · edited May 23 '17 at 12:27

0

Hibernate requires that entity tables have primary keys. End of story.

Hibernate without Primary Key

edited May 23 '17 at 12:27

Community

1
1

answered Aug 29 '14 at 06:59

heikkim

2,955
2
24
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score 0 · Accepted Answer · answered Aug 29 '14 at 07:36

You are getting NullPointerException at the line t.commit(); in your updateUser(...) method, because your transaction variable t is initialized to null at line Transaction t = null;.

So just add this line in updaeUser method to fix your issue:

t = session.beginTransaction();

Nullpointer Exception while calling session.get() method in Hibernate

2 Answers2