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Sanjeev Kumar
java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot be
February 26, 2013 10:19 PM
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Sanjeev Kumar

Rank: New Member

Posts: 6

Join Date: February 26, 2013

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Hi everyone,
I am using Liferay CE 6.1, tomcat 7.
I am developing custom portlets in my liferay project.
I am connecting to external database MySQL.
I need to add hibernate3.jar to implement my custom API's in my portlet.
I tried adding the hibernate3.jar explicitly in my WEB-INF/lib folder and also tried adding through liferay-plugin-package.properties to include the dependency jar which liferay uses.
But I get the same error, saying org.hibernate.HibernateException: Could not instantiate dialect class

BeanLocator not set for servlet context,

java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot be cast to org.hibernate.dialect.Dialect.

org.hibernate.HibernateException: Could not instantiate dialect class.

Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'liferayHibernateSessionFactory' defined in ServletContext resource [/WEB-INF/classes/META-INF/hibernate-spring.xml]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Could not instantiate dialect class.

I am not able to go forward until I get rid of this problem, please I need help, thanks in advance...
MICHAIL MOUDATSOS
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
March 1, 2013 5:58 AM
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MICHAIL MOUDATSOS

Rank: Regular Member

Posts: 110

Join Date: October 4, 2011

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I think ou should first mention what kind of frameworks you use, i.e. "Do you use plain Hibernate?", "Are you using Spring?". This will help people understand your situation better. E.g., for the plain hibernate case, I have tried that in the past and there was no problem. I just had to add hibernate and all of its dependencies to my lib folder (and of course initialize it properly emoticon).
David H Nebinger
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
March 1, 2013 6:24 AM
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David H Nebinger

Rank: Liferay Legend

Posts: 7153

Join Date: September 1, 2006

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You're encountering class loader issues...

Basically you've got your own hibernate jar loaded in your class loader, but the liferayHibernateSessionFactory instance is defined in Liferay's class loader. In Liferay's class loader, it has already created the connection and established the dialect to use, in this case a MySQLDialect.

So you're trying to reuse the connection from their class loader in your own class loader and, of course, although both have a Dialect interface defined, they are completely different class and cannot be cast around.
Sanjeev Kumar
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
March 6, 2013 8:51 PM
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Sanjeev Kumar

Rank: New Member

Posts: 6

Join Date: February 26, 2013

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But the error occurs when the hibernate jar is added in lib folder, not while implementing the API's which are built on hibernate.
MICHAIL MOUDATSOS
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
March 6, 2013 9:03 PM
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MICHAIL MOUDATSOS

Rank: Regular Member

Posts: 110

Join Date: October 4, 2011

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Sanjeev Kumar:
But the error occurs when the hibernate jar is added in lib folder, not while implementing the API's which are built on hibernate.
So, you mean you haven't written a single line of code, not even a configuration file, anything?
Sanjeev Kumar
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
March 7, 2013 2:28 AM
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Sanjeev Kumar

Rank: New Member

Posts: 6

Join Date: February 26, 2013

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we are connecting to different (application) Database using hibernate.
We created API to connect to the other application database. The API is using hibernate to connect the other application.
Sahil Shaikh
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
May 28, 2014 2:52 AM
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Sahil Shaikh

Rank: New Member

Posts: 1

Join Date: May 21, 2014

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Does anyone one have any success with hibernate?
Di He
RE: java.lang.ClassCastException: org.hibernate.dialect.MySQLDialect cannot
September 19, 2014 4:40 PM
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Di He

Rank: New Member

Posts: 13

Join Date: January 28, 2008

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I started a liferay6.2.2 service builder portlet by using the eclipselink 2.5.1 and JPA 2.1 to get data from external database, my service builder portlet also have tables created by service.xml. I tested the service builder portlet in my LR6.2.2 tomcat server and it works well.

I then deployed my service builder portlet on LR6.2.2 Glassfish 3 server, I got an error says it can't created the EntityManagerFactory from the persistence unit defined in persistence.xml. So I tried using hibernate JPA to replace the eclipselink, then I ran into the same issue you guys are talking about.

I think glassfish 3 server has older version of eclipselink installed. I am going to try to upgrade it to 2.5.1 and see my portlet will work or not.

If you are running liferay on tomcat, you could try what I did. Good luck.