exception with JPA application

[Anil Deshpande]

This is the code of the application:

 
package com.sample.bean;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Employee {

	@Id
	private int id;
	private String name;
	
	
	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;
	}
	
	
}
   

persistance.xml

 <?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
	<persistence-unit name="FirstJPA" transaction-type="RESOURCE_LOCAL">
	<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
	<class>com.sample.bean.Employee</class>
	<properties>

		<property name="toplink.jdbc.url" value="jdbc:mysql://localhost/experiments"/>
		<property name="toplink.jdbc.user" value="root"/>
		<property name="toplink.jdbc.driver" value="com.mysql.jdbc.Driver"/>
		<property name="toplink.jdbc.password" value=""/>
		<property name="toplink.ddl-generation" value="create-tables"/>
		<property name="toplink.jdbc.read-connections.max" value="1"/>
		<property name="toplink.jdbc.write-connections.max" value="1"/>
		<property name="toplink.jdbc.write-connections.min" value="1"/>
		<property name="toplink.logging.level" value="SEVER"/>

	</properties>
		
	</persistence-unit>
</persistence>
   

main method:

    
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

import com.sample.bean.Employee;


public class TestJPA {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		EntityManagerFactory emf=Persistence.createEntityManagerFactory("FirstJPA");
		EntityManager entityManager=emf.createEntityManager();
		EntityTransaction entityTransaction=entityManager.getTransaction();
		
		entityTransaction.begin();
		System.out.println("Entering enetity in the database");
		Employee employee=new Employee();
		employee.setId(110);
		employee.setName("Veeru");
		entityManager.persist(employee);
		if(entityTransaction!=null)
		{
			entityTransaction.commit();
		}
		
		System.out.println("Updated in the database");
	}

}

And the Exception it is throwing is:

   [EL Info]: 2010-07-14 22:40:50.544--ServerSession(28705408)--EclipseLink, version: Eclipse Persistence Services - 1.1.2.v20090612-r4475
[EL Severe]: 2010-07-14 22:40:50.563--ServerSession(28705408)--Local Exception Stack: 
Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:375)
	at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:90)
	at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
	at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:583)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:227)
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:255)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:111)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:163)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:150)
	at TestJPA.main(TestJPA.java:18)

Exception in thread "main" javax.persistence.PersistenceException: Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:272)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:111)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:163)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:150)
	at TestJPA.main(TestJPA.java:18)
Caused by: Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:375)
	at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:90)
	at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
	at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:583)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:227)
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:255)
	... 4 more
 

How to Solve this Problem?

[Shannon McGee]

Hi Anil,

The first thing that caught my eye is that your password is never set. Did you remove it to post the example, or forgot to set it in your code?

It looks like your persistence.xml file is never read. Is it on the classpath?

-Shannon

[James Sutherland]

You are using the wrong persistence unit properties for your connection as you are using EclipseLink, not TopLink,

change to:
<property name="eclipelink.jdbc.url" value="jdbc:mysql://localhost/experiments"/>
<property name="eclipelink.jdbc.user" value="root"/>
<property name="eclipelink.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="eclipelink.jdbc.password" value=""/>
<property name="eclipelink.ddl-generation" value="create-tables"/>
<property name="eclipelink.jdbc.connections.min" value="1"/>
<property name="eclipelink.jdbc.connections.max" value="2"/>
<property name="eclipelink.logging.level" value="FINEST"/>

or, since you are using EclipseLink 1.2 which supports JPA 2.0 use the standard JPA 2.0 JDBC properties:
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/experiments"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.password" value=""/>
<property name="eclipelink.ddl-generation" value="create-tables"/>
<property name="eclipelink.jdbc.connections.min" value="1"/>
<property name="eclipelink.jdbc.connections.max" value="2"/>
<property name="eclipelink.logging.level" value="FINEST"/>

[Anil Deshpande]

There is no password set for the database. that is why I have not given the password. And After I did the changes to the persistance .xml as indicated by James Still I am getting the exception? I did the both the changes. But still it gives the same problem.

The Exception is

   
[EL Info]: 2010-07-15 22:45:57.064--ServerSession(28705408)--EclipseLink, version: Eclipse Persistence Services - 1.1.2.v20090612-r4475
[EL Severe]: 2010-07-15 22:45:57.083--ServerSession(28705408)--Local Exception Stack: 
Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:375)
	at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:90)
	at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
	at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:583)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:227)
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:255)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:111)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:163)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:150)
	at TestJPA.main(TestJPA.java:18)

Exception in thread "main" javax.persistence.PersistenceException: Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:272)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:111)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:163)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:150)
	at TestJPA.main(TestJPA.java:18)
Caused by: Exception [EclipseLink-4021] (Eclipse Persistence Services - 1.1.2.v20090612-r4475): org.eclipse.persistence.exceptions.DatabaseException
Exception Description: Unable to acquire a connection from driver [null], user [null] and URL [null].  Verify that you have set the expected driver class and URL.  Check your login, persistence.xml or sessions.xml resource.  The jdbc.driver property should be set to a class that is compatible with your database platform
	at org.eclipse.persistence.exceptions.DatabaseException.unableToAcquireConnectionFromDriverException(DatabaseException.java:375)
	at org.eclipse.persistence.sessions.DefaultConnector.connect(DefaultConnector.java:90)
	at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162)
	at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:583)
	at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:227)
	at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:255)
	... 4 more
 

Just to check whether I am using proper driver and url, I tried jdbc program with connection and manager, It works perfectly fine. I don't understand where the problem is?