title: Class [org.apache.derby.jdbc.ClientDriver] not found. When trying to connect to db
body: <p>I have set up a project in Netbeans, created a script, made a new database with javadb. I can connect to it by gui - display the tables contents etc, but when i run an application with:</p>
  
  <pre><code> EntityManager em = Persistence.createEntityManagerFactory("lab5PU").createEntityManager();
  </code></pre>
  
  <p>i get this quite long exception:</p>
  
  <pre><code>[EL Info]: 2013-04-05 21:40:45.554--ServerSession(1198260109)--EclipseLink, version: Eclipse Persistence Services - 2.3.0.v20110604-r9504
  [EL Severe]: 2013-04-05 21:40:45.574--ServerSession(1198260109)--Local Exception Stack: 
  Exception [EclipseLink-4003] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DatabaseException
  Exception in thread "AWT-EventQueue-0" javax.persistence.PersistenceException: Exception [EclipseLink-4003] (Eclipse Persistence Services - 2.3.0.v20110604-r9504): org.eclipse.persistence.exceptions.DatabaseException
  Exception Description: Configuration error.  Class [org.apache.derby.jdbc.ClientDriver] not found.
  Exception Description: Configuration error.  Class [org.apache.derby.jdbc.ClientDriver] not found.
      at org.eclipse.persistence.exceptions.DatabaseException.configurationErrorClassNotFound(DatabaseException.java:82)
  </code></pre>
  
  <p>I can see the javadb drivers in the driver section in services, so i have no idea what the error might be.</p>
  
  <p>EDIT: persistance.xml as requested:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;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"&gt;
    &lt;persistence-unit name="lab5PU" transaction-type="RESOURCE_LOCAL"&gt;
      &lt;provider&gt;org.eclipse.persistence.jpa.PersistenceProvider&lt;/provider&gt;
      &lt;class&gt;lab5.Colleagues&lt;/class&gt;
      &lt;properties&gt;
        &lt;property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/lab5"/&gt;
        &lt;property name="javax.persistence.jdbc.password" value="mypass"/&gt;
        &lt;property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/&gt;
        &lt;property name="javax.persistence.jdbc.user" value="admin"/&gt;
        &lt;property name="eclipselink.ddl-generation" value="create-tables"/&gt;
      &lt;/properties&gt;
    &lt;/persistence-unit&gt;
  &lt;/persistence&gt;
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/8J8vx.png" alt="enter image description here"></p>