3

I know that there are similar questions already, but the answers there didn't help me. So please would you mind to take a look at my particular question?

I am not very experienced with Hibernate yet and hava a problem when trying to create test data for my local database with Hibernate 4.3 and PostgreSQL.

I had another project where I did this exactly the same way and there it worked, so I did exactly the same setup but with another database, but now in my current project I get the following exception:

exception.DBException: Could not configure Hibernate!
    at dao.BenutzerDAO.<init>(BenutzerDAO.java:48)
    at export.ExportDBSchema.main(ExportDBSchema.java:16)
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [org.postgresql.Driver]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:245)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.loadDriverIfPossible(DriverManagerConnectionProviderImpl.java:200)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildCreator(DriverManagerConnectionProviderImpl.java:156)
    at org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:95)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:89)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:206)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:178)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.buildJdbcConnectionAccess(JdbcServicesImpl.java:260)
    at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:94)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:89)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:206)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:178)
    at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1885)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1843)
    at dao.BenutzerDAO.<init>(BenutzerDAO.java:45)
    ... 1 more
Caused by: java.lang.ClassNotFoundException: Could not load requested class : org.postgresql.Driver
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:230)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:340)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:242)
    ... 15 more

I searched for possible solutions, but none of them worked for me:

-)Specify Classpath to jar in Manifest.mf -> Did not work -)Place the postgresql-9.4.1208.jre6.jar in lib folder under WEB-INF -> Did not work -)Specify hibernate.cfg.xml file in Configuration().configure(); -> Did not work

I use Glassfish 4.1 and the org.postgres.Driver.class is existing, so why is it not found?

My hibernate.cfg.xml:

<?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>
    <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
    <property name="hibernate.connection.url">jdbc:postgresql://localhost:5432/Testdb</property>
    <property name="hibernate.connection.username">username</property>
    <property name="hibernate.hbm2ddl.auto">create-drop</property>
    <property name="hibernate.connection.password">password</property>
    <mapping class="entity.Benutzer"/>
  </session-factory>
</hibernate-configuration>

Method in DAO class where the exception occurs:

try {
            if (sessionFactory == null) {
                Configuration conf = new Configuration().configure();

                StandardServiceRegistryBuilder builder
                        = new StandardServiceRegistryBuilder();
                builder.applySettings(conf.getProperties());

                sessionFactory = conf.buildSessionFactory(builder.build());
            }
        } catch (Throwable ex) {
            throw new DBException("Could not configure Hibernate!", ex);
        }

I would be very thankful for every answer.

2 Answers 2

9

If you are using maven or gradle.

You can add this to ur pom.xml for maven

<!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.2.4</version>
</dependency>

And this for gradle

// https://mvnrepository.com/artifact/org.postgresql/postgresql
compile group: 'org.postgresql', name: 'postgresql', version: '42.2.4'
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Comments

4

You were close!

You need to place your postgresql-<version>.jar directly in the lib folder of your servlet container.
For instance, if you're working with Apache Tomcat, simply drop your jar under <TOMCAT_ROOT>/lib and you should be all set.

2 Comments

Thank you for your answer. Unfortunately it still throws the exception java.lang.ClassNotFoundException: Could not load requested class : org.postgresql.Driver. I tried to put the jar in every lib folder I could find in my project and server folder but it did not work either
In the meantime the problem could be solved. It had something to do with the location of the jar but I don't really know what I did different this time, but now it works :) Thanks again.

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