Could not load com.mysql.jdbc.SQLError

[Suresh Khant]

Hi All,

I am developing Jsf 1.2 application using mysql database, deployed using jboss 4 Application Server , the application works fine without any bugs but I have found the following error in jboss logs

BTW , the same error is displayed so many times in jboss logs (note that this error does not effect the working of the application)

17:06:33,579 INFO  [DriverManagerConnectionProvider] cleaning up connection pool: jdbc:mysql://localhost:3306/students_db
17:06:33,580 INFO  [WebappClassLoader] Illegal access: this web application instance has been stopped already.  Could not load com.mysql.jdbc.SQLError.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1244)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1204)
	at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
	at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3134)
	at com.mysql.jdbc.MysqlIO.quit(MysqlIO.java:1616)
	at com.mysql.jdbc.ConnectionImpl.realClose(ConnectionImpl.java:4223)
	at com.mysql.jdbc.ConnectionImpl.cleanup(ConnectionImpl.java:1257)
	at com.mysql.jdbc.ConnectionImpl.finalize(ConnectionImpl.java:2663)
	at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
	at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
	at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)
17:06:33,581 INFO  [DriverManagerConnectionProvider] cleaning up connection pool: jdbc:mysql://localhost:3306/students_db
17:06:33,582 INFO  [WebappClassLoader] Illegal access: this web application instance has been stopped already.  Could not load com.mysql.jdbc.SQLError.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1244)
	at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1204)
	at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
	at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:3134)
	at com.mysql.jdbc.MysqlIO.quit(MysqlIO.java:1616)
	at com.mysql.jdbc.ConnectionImpl.realClose(ConnectionImpl.java:4223)
	at com.mysql.jdbc.ConnectionImpl.cleanup(ConnectionImpl.java:1257)
	at com.mysql.jdbc.ConnectionImpl.finalize(ConnectionImpl.java:2663)
	at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
	at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
	at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)
17:06:33,583 INFO  [DriverManagerConnectionProvider] cleaning up connection pool: jdbc:mysql://localhost:3306/students_db

[Tim Holloway]

Apparently you are wrong about the "without any bugs" part.

I can't really tell what is wrong, except that it almost certainly has nothing to do with JSF. The two most likely causes I can think of are these:

1. You are using JDBC connection objects but not properly releasing them in one or more webapps.

2. You are spawning threads that use JDBC in a way that violates the JEE restrictions on threading.

[Suresh Khant]

Thanks for your reply ,

here is some of my code for dealing with database

public Integer createStudentInfo(StudentInfo studentInfo) {

	Session session = HibernateUtil.getSessionFactory().openSession();
		Transaction transaction = null;
		Integer studentId = null;
		try {
			transaction = session.beginTransaction();
			studentId = (Integer) session.save(studentInfo);
			transaction.commit();
		} catch (HibernateException e) {
			transaction.rollback();
			e.printStackTrace();
		} finally {
			session.close();
		}
		return studentId;
	}

}

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {
	private static final SessionFactory sessionFactory;
	static {
		try {
			sessionFactory = new Configuration().configure()
					.buildSessionFactory();
		} catch (Throwable ex) {
			System.err.println("Initial SessionFactory creation failed." + ex);
			throw new ExceptionInInitializerError(ex);
		}
	}

	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
                                         "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 <session-factory name="studentSessionFactory">
  <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
   <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/students_db</property> 

  
  <property name="hibernate.connection.username">root</property>
  <property name="hibernate.connection.password">root</property>
  <property name="hibernate.connection.pool_size">10</property>
  <property name="show_sql">true</property>
  <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
  <property name="hibernate.hbm2ddl.auto">update</property>
  <!-- Mapping files -->
  <mapping resource="com/example/student/StudentInfo.hbm.xml"/>

 </session-factory>
</hibernate-configuration>

[James Boswell]

Rather than

 session.close();

Try:

 session.endTransaction();

[Suresh Khant]

Thanks James Boswell for your reply ,

1. session.endTransaction();

No such method , the nearest method to your suggested method is

session.flush();

I have replaced

session.close();

with

session.flush();

but it is the same error as well as new error

ERROR [STDERR] org.hibernate.HibernateException: Illegal attempt to associate a collection with two open session

[Suresh Khant]

Any suggestions

[Suresh Khant]

Any suggestions

[Tim Holloway]

What directory is your MySQL driver jar in?

[Suresh Khant]

Thanks Tim Holloway

What directory is your MySQL driver jar in?

I am using maven , mysql jar locates in the directory

/home/testuser/.m2/repository/mysql/mysql-connector-java/5.1.5

[Tim Holloway]

That didn't help. Maven won't be available when you run the app in production, nor will your IDE. I need to know where the driver jar was installed in your web application server.

[Suresh Khant]

Thanks Tim Holloway for your reply ,

I need to know where the driver jar was installed in your web application server

I have local jboss application server 4.2 , mysql 5 , so everything (jboss application server , mysql database server , ....etc) is running locally in the same machine

[Tim Holloway]

Suresh Khant wrote:Thanks Tim Holloway for your reply ,

I need to know where the driver jar was installed in your web application server

I have local jboss application server 4.2 , mysql 5 , so everything (jboss application server , mysql database server , ....etc) is running locally in the same machine

It doesn't matter what machines are being used. What matters is that JBoss does not come with database drivers. You have to manually install whatever database drivers you'll be using. If you install them in the wrong place, it can cause problems. I have a strong suspicion that that is what is wrong here.

[Suresh Khant]

Thanks Tim Holloway for your reply ,

You have to manually install whatever database drivers you'll be using. If you install them in the wrong place

How to install database drivers ? do you mean adding the mysql jar file to the build path ? what is the right place for installation it ?

Your help, support and reply is really appreciated

[Tim Holloway]

The build path does not exist when a production server runs. It only exists when the application is being built.

You have some basic things to learn about JBoss and how it interacts with databases. They have nothing to do with JSF, so I'm going to move this thread over to the JBoss forum.

[Jaikiran Pai]

Tim is right - there's a difference between build time environment of an application and the runtime environment of an application. As for the question about where to place the JDBC driver jar(s), it should go in JBOSS_HOME/server/<servername>/lib folder.

[Suresh Khant]

Thanks Jaikiran Pai for your reply,
I have copied mysql jar file into JBOSS_HOME/server/messaging/lib but am still getting the same error

[Suresh Khant]

All the suggestions are appreciated

[Jaikiran Pai]

Suresh Khant wrote:
I have copied mysql jar file into JBOSS_HOME/server/messaging/lib but am still getting the same error

What command do you use to start the server and please post the entire exception stacktrace that you see after copying that driver jar to that location.

[Suresh Khant]

Thanks Jaikiran Pai for you reply,

What command do you use to start the server and please post the entire exception stacktrace that you see after copying that driver jar to that location.

I am starting jboss server from eclipse ,

Everything goes correctly after copying that driver jar to that location.(no error)

the error will be generated after long time of deploying (sometimes after one hour of deployment)

I have already post the stacktrace in my first post

Thaking you in advance