Classcast Exception using GAE/J+Spring+JPA+MySQL

Hi,

I am developing an application using GAE/J+Spring+JPA+MySQL.

When i retrieve the data from MySQL Database i am getting the following Error.

org.datanucleus.store.rdbms.RDBMSManager cannot be cast to org.datanucleus.store.appengine.DatastoreManager

Can anybody please help me where i am doing wrong.

Following is my persistence.xml file:

<?xml version="1.0" encoding="UTF-8" ?>

<persistence 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"

version="1.0">

<persistence-unit name="transactions-optional">

<provider>org.datanucleus.store.appengine.jpa.DatastorePersistenceProvider</provider>

<class>ENTITY-CLASS-NAME</class>

<properties>

<property name="datanucleus.NontransactionalRead" value="true" />

<property name="datanucleus.NontransactionalWrite" value="true" />

<property name="javax.persistence.jdbc.driver"

value="com.google.appengine.api.rdbms.AppEngineDriver" />

<property name="datanucleus.ConnectionURL"

value="jdbc:google:rdbms://INSTACE-NAME/DATABASE_NAME" />

<property name="datanucleus.autoCreateTables" value="false" />

<property name="datanucleus.storeManagerType" value="rdbms" />

<property name="datanucleus.jpa.level" value="JPA1" />

<property name="datanucleus.jpa.addClassTransformer" value="false" 

/>

</properties>

</persistence-unit>

</persistence>