Java/Hibernate - Exception: The internal connection pool has reached its maximum size and no connections are currently available
I'm using Hibernate for the first time in a university project and I'm still new to it. I think I followed all the instructions given by my professor and some tutorials I read, but I keep getting the Exception in the title:
Exception in thread "main" org.hibernate.HibernateException: The internal connection pool has reached its maximum size and no connection is currently available!
All I want to do is store an object ( AbitazioneDB ) into an already created MySql database. Here is my config file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Connection to the database -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/AllarmiDomesticiDB</property>
<!-- Credentials -->
<property name="hibernate.connection.username">root</property>
<property name="connection.password">password</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="show_sql">true</property>
<!-- Entity -->
<mapping class="it.allarmiDomestici.centraleOperativaRemota.dbWrapper.AbitazioneDB" />
</session-factory>
</hibernate-configuration>
Here is my AbitazioneDB class (I will omit the getter and setter methods):
@Entity
@Table(name="abitazioni")
public class AbitazioneDB {
@Id
@GeneratedValue
@Column(name="id")
private Integer id;
@Column(name="indirizzo")
private String indirizzo;
@Column(name="nome_proprietario")
private String nomeProprietario;
@Column(name="tel_proprietario")
private String telProprietario;
public AbitazioneDB(){
super();
}
public AbitazioneDB save(){
SessionFactory sf = HibernateUtil.getSessionFactory();
Session session = sf.getCurrentSession();
session.beginTransaction();
Integer id = (Integer) session.save(this);
this.setId(id);
session.getTransaction().commit();
session.close();
return this;
}
}
Here is my HibernateUtil class:
public class HibernateUtil {
private static SessionFactory sessionFactory;
private static SessionFactory createSessionFactory() {
sessionFactory = new Configuration().configure().buildSessionFactory();
return sessionFactory;
}
public static SessionFactory getSessionFactory() {
if (sessionFactory == null)
sessionFactory = createSessionFactory();
return sessionFactory;
}
}
Here is my TestHibernate class with the following mainmethods:
public class TestHibernate {
public static void main(String[] args) {
AbitazioneDB ab = new AbitazioneDB();
ab.setIndirizzo("Via Napoli, 29");
ab.setNomeProprietario("Mario Rossi");
ab.setTelProprietario("3333333333");
ab.save();
System.out.println("Ok!");
}
}
When I run TestHibernate I always get that exception and I don't know why. Maybe I should change the connection.pool_sizeproperties, but if I do I just seem to get more errors. Can someone help me?
Try this:
HibernateUtil：
public static Session getHibernateSession() {
final SessionFactory sf = new Configuration()
.configure("yourConfig.cfg.xml").buildSessionFactory();
// factory = new Configuration().configure().buildSessionFactory();
final Session session = sf.openSession();
return session;
}
Instead of using SessionFactory, use Session:
final Session session = HibernateUtil.getHibernateSession();
Then use:
Transaction tx = session.beginTransaction();
// all your methods
tx.commit();
session.close();
Hope this helps.
If you don't need it, you won't actually have that connection pool property in your hbm.