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How to validate only specific tables using hibernate

Im using hibernate.hbm2ddl.auto=validate in my persistence.xml. But the problem I have is my project connects to multiple databases using multiple data sources.
So when I turn on validation then it will try to find out tables in wrong databases since they are annotated as tables. Is there any way to specify which tables each validator should look into ? following is the part of persistence.xml I have
<persistence-unit name="primary">
<jta-data-source>java:jboss/datasources/oneDataSource</jta-data-source>
<shared-cache-mode>DISABLE_SELECTIVE</shared-cache-mode>
<properties>
<property name="hibernate.hbm2ddl.auto" value="validate"/>
</properties>
</persistence-unit>
<persistence-unit name="mymysql">
<jta-data-source>java:jboss/datasources/twoDataSource</jta-data-source>
<shared-cache-mode>DISABLE_SELECTIVE</shared-cache-mode>
<properties>
<property name="hibernate.hbm2ddl.auto" value="validate"/>
</properties>
</persistence-unit>

WAS Liberty 8.5.5.4, JPA 2.0 - discovered implementations: NONE

I was able to get JPA working with eclipse Luna and installing eclipseLink (and created a User Lib with the 3 jars).
However, I have now moved to Rational Application Developer (RAD) and attempting to use the JPA that is delivered with WAS Liberty. I initially used RAD JPA facet to configure JPA and then edited persistence.xml.
I am getting this error:
Caused by: javax.persistence.PersistenceException: No persistence providers available for "test2" after trying the following discovered implementations: NONE
I assume (always dangerous) the NONE is a configuration error and I cannot do anything until that is resolved...
I have copied the wlp\dev\api\spec\com.ibm.ws.javaee.persistence.2.0_1.0.1.jar into WEB-INF/lib and included that in my java build path.
As you can see below, I was guessing my provider was not correct, and tried several values...
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
<persistence-unit name="test2" transaction-type="RESOURCE_LOCAL">
<!-- provider>org.eclipse.persistence.jpa.PersistenceProvider</provider-->
<!-- provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider-->
<provider>com.ibm.websphere.persistence.PersistenceProviderImpl</provider>
<non-jta-data-source>java:comp/env/New Generic JDBC</non-jta-data-source>
<class>com.ibm.analytics.jpa.Dimtask</class>
<properties>
<property name="openjpa.jdbc.Schema" value="RM"/>
<property name="javax.persistence.jdbc.url" value="jdbc:netezza://netezza-1.site.ibm.com:5480/DATABASENAME"/>
<property name="javax.persistence.jdbc.user" value="jspoon"/>
<property name="javax.persistence.jdbc.password" value="xxxxxxx"/>
<property name="javax.persistence.jdbc.driver" value="org.netezza.Driver"/>
</properties>
</persistence-unit>
</persistence>
What else can I do to get past the NONE?
Here is the updated version of persistence.xml, I just commented out the provider.
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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_2_0.xsd">
<persistence-unit name="test2" transaction-type="RESOURCE_LOCAL">
<!-- provider>org.eclipse.persistence.jpa.PersistenceProvider</provider-->
<!-- provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider-->
<!-- provider>com.ibm.websphere.persistence.PersistenceProviderImpl</provider-->
<non-jta-data-source>java:comp/env/New Generic JDBC</non-jta-data-source>
<class>com.ibm.analytics.jpa.Dimtask</class>
<properties>
<property name="openjpa.jdbc.Schema" value="RM"/>
<property name="javax.persistence.jdbc.url" value="jdbc:netezza://netezza-1.boulder.ibm.com:5480/BACC_TST_ISHANGO_DW"/>
<property name="javax.persistence.jdbc.user" value="jspoon"/>
<property name="javax.persistence.jdbc.password" value="C0ke4y0u"/>
<property name="javax.persistence.jdbc.driver" value="org.netezza.Driver"/>
</properties>
</persistence-unit>
</persistence>
I created my Entity class using JPA Tooling, and using a simple junit test to call a named query. The first step is to create the EMF and it is a static in my class (so none of the test is actually running, it is failing at instantiation creating the static variable):
static EntityManagerFactory emf = Persistence.createEntityManagerFactory( "test2" );
This is the exact same code as used before with eclipse and eclipseLink.

OpenJPA - ArgumentException: JDBC driver or data source class name

I'm creating an OpenJPA application with maven.
The application starts, but if I try to access a database-entity, I get the following exception:
HTTP Status 500 - <openjpa-2.2.2-r422266:1468616 fatal user error> org.apache.openjpa.persistence.ArgumentException: The persistence provider is attempting to use properties in the persistence.xml file to resolve the data source. A Java Database onnectivity (JDBC) driver or data source class name must be specified in the openjpa.ConnectionDriverName or javax.persistence.jdbc.driver property. The following properties are available in the configuration: "org.apache.openjpa.jdbc.conf.JDBCConfigurationImpl#442ce698".
The persistence.xml is located in META-INF and is under control by Netbeans 8.
The ConnectionDriverName is set as the following:
<property name="openjpa.ConnectionDriverName" value="org.apache.commons.dbcp.BasicDataSource"/>
My src\main\java\META-INF\persistence.xml (class-tags reduced and database-settings changed):
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="PersistenceUnit" transaction-type="RESOURCE_LOCAL">
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
<class>com.example.test.my.entities.User</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
<properties>
<property name="openjpa.jdbc.SynchronizeMappings" value="buildSchema"/>
<property name="openjpa.Log" value="DefaultLevel=INFO, Tool=INFO, SQL=TRACE"/>
<property name="openjpa.jdbc.DBDictionary" value="org.apache.openjpa.jdbc.sql.MySQLDictionary"/>
<property name="openjpa.ConnectionDriverName" value="org.apache.commons.dbcp.BasicDataSource"/>
<property name="openjpa.ConnectionFactoryProperties" value="PrettyPrint=true, PrettyPrintLineLength=80, PrintParameters=true"/>
<property name="openjpa.ConnectionProperties" value="DriverClassName=com.mysql.jdbc.Driver,
Url=jdbc:mysql://localhost:3306/database?autoReconnect=true,
Username=usr,
Password=pwd,
MaxWait=60000,
TestOnBorrow=true,
validationQuery=select 1"/>
</properties>
</persistence-unit>
</persistence>
I'm using Tomcat 8 (same result for Tomcat 7 or Tomee).

solved it by switching to eclipse, because it seems like netbeans having some problems with the persistence.xml.
In eclipse I had to use the following m2e-connector:
https://github.com/hwellmann/m2eclipse-extras/raw/master/p2/ (eclipse software repository url)

Why do we have to give database credentials in persistence.xml

We are using JPA 2.0 and we created the datasource in websphere and tried to access the database through the J2SE application. We are getting Invalid Username and password error. If we give the user name and password in persistence.xml it works fine.
Please anybody explain me why do we have to give the DB credentials in persistence.xml since we have the data source.
Note: Data Source was created successfully and the test was success.
persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
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_2_0.xsd">
<persistence-unit name="Printer">
<jta-data-source>jdbc/TestDataSource</jta-data-source>
<properties>
<property name="openjpa.Optimistic" value="false" />
<property name="openjpa.LockManager" value="pessimistic" />
<property name="javax.persistence.jdbc.user" value="admin" />
<property name="javax.persistence.jdbc.password" value="admin#2" />
</properties>
</persistence-unit>
</persistence>

It seems that the datasource is not configured correctly in websphere. Test the database connection through the websphere console to verify the configuration.
A DataSource has 2 methods to get a Connection. It seems that your jpa implementation uses DataSource.getConnection(String username, String password) if you provide the credentials via properties.
The connection properties are intented to use in a Java SE environment. In JEE you should prefer the JNDI lookup. See section 8.2.1.9 of the JPA 2.0 specification.

You don't need to specify the credentials in your application. Just access your database via JNDI, specifying the name of the datasource you've created in the WS.
One way is to configure persistence unit using the pre-configured datasource (Please double check if it is configured correctly - the test feature is available in WS)
<persistence-unit name="default" transaction-type="JTA">
<provider>
oracle.toplink.essentials.PersistenceProvider
</provider>
<jta-data-source>
jdbc/MyDataSource
</jta-data-source>
<properties>
<property name="toplink.logging.level" value="INFO"/>
</properties>
</persistence-unit>
If the datasource is not configured on the application container side, you may set it up yourself on the application side. For example, you need a number of the applications each one has its own database connection config.
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
<provider>
oracle.toplink.essentials.PersistenceProvider
</provider>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="toplink.logging.level" value="INFO"/>
<property name="toplink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
<property name="toplink.jdbc.url" value="jdbc:oracle:thin:#myhost:l521:MYSID"/>
<property name="toplink.jdbc.password" value="tiger"/>
<property name="toplink.jdbc.user" value="scott"/>
</properties>
</persistence-unit>
Your persistence.xml has the config for both ways. Remove the unnecessary code and try again.

With derby/jpa/tomcat, the database is always already booted

I'm trying to use jpa with tomcat, with Derby. But I get this message : Caused by: ERROR XSDB6: Another instance of Derby may have already booted the database.
My persistence.xml is something like that :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="contribs" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:derby:~/contribs;create=true"/>
<property name="javax.persistence.jdbc.password" value="sa"/>
<property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.EmbeddedDriver"/>
<property name="javax.persistence.jdbc.user" value="sa"/>
<property name="eclipselink.ddl-generation" value="create-tables"/>
</properties>
</persistence-unit>
</persistence>
I use a ServletContextListener, annotated with #WebListener().
On contextInitialized I get a EntityManagerFactory and an EntityManager, and I close all on contextDestroyed.
I see with log tomcat call twice my ServletContextListener (I don't understand why), and the second time I get the error message.
Also I use Netbeans.
How can I resolve that ? Thanks.

Are you hot-redeploying your application into Tomcat? Tomcat appears to frequently keep multiple copies of the web-app running, in separate application class loaders, and only one copy of your web-app is able to open Derby at a time.
One possibility is to switch from the Embedded version of Derby to the Client-Server version.
Another possibility is to restart Tomcat when the problem occurs.