org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer]
hibernate, hibernate-mapping, java
Solution
You should explicitly define no-arg constructor. This is a requirement from Hibernate to all POJOs.
Detailed explanation could be found here: https://stackoverflow.com/a/2971717/283426
Problem
I am developing a web application using Hibernate framework. I got this error when trying to run webapp. Error Console: ``` Exception caught in Create Account Dataorg.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer] java.lang.NullPointerException ``` My mapping file (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="org.vgec.bean.CreateAccount" table="CreateAccount" > <id name="enrollment_number" type="java.lang.String"> <column name="enrollment_number" length="20"/> <generator class="assigned" /> </id> <property name="activation_code" type="java.lang.String"> <column name="activation_code" length="50"/> </property> </class> </hibernate-mapping> ``` DataAccessObject file code: ``` public void addCreateAccount(CreateAccount act) throws Exception { Session session = null; try{ //this step will read hibernate.cfg.xml SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory(); session = sessionFactory.openSession(); Transaction tx = session.beginTransaction(); session.save(act); tx.commit(); }catch(Exception e) { System.out.println("Exception caught in Create Account Data" + e); }finally{ session.flush(); session.close(); } } ``` Here in Above code Exception is thrown - the string in catch is displayed in the error in console. Here is my bean Or POJO file: ``` package org.vgec.bean; public class CreateAccount { private String enrollment_number; private String activation_code; public String getEnrollment_number() { return enrollment_number; } public void setEnrollment_number(String enrollment_number) { this.enrollment_number = enrollment_number; } public String getActivation_code() { return activation_code; } public void setActivation_code(String activation_code) { this.activation_code = activation_code; } } ``` - I have checked the other threads solutions. - I have included `javaassist.jar` file - All the setter and getter do not have any typos. - I'm also having `java.lang.NullPointerException`. What is the root cause of this error?