Erro - No Persistence provider for EntityManager

<?xml version="1.0" encoding="UTF-8"?>
 <persistence xmlns="http://java.sun.com/xml/ns/persistence"  
 xmlnssi="http://www.w3.org/2001/XMLSchema-instance" version="1.0"
  xsi:SchemaLocation="http://java.sun.com/xml/ns/persistence
  <a href="http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" target="_blank" rel="nofollow">http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd</a>">
     
     
 <persistence-unit name="persistencia" >
  <provider>
    oracle.toplink.essentials.PersistenceProvider
  </provider>
     
 <class>vo.privilegio</class>
 
 <properties>
     <property name="toplink.jdbc.driver" value="oracle.jdbc.driver.OracleDriver"/>
     <property name="toplink.jdbc.url" value="jdbc:oracle:lalalalaalal"/>
     <property name="toplink.jdbc.user" value="lala"/>
     <property name="toplink.jdbc.password" value="lalala"/>
 </properties>
 
 </persistence-unit>
 
 </persistence>

@Entity
 public class privilegio implements java.io.Serializable {
      @Id
      @SequenceGenerator(name="PRIVILEGIO_ID")
      @GeneratedValue(generator="PRIVILEGIO_ID") 
      private int Privilegio_Id;
      
      @Column
      private String Descricao;
           
     ... gets e sets

public class privilegio_dao {
     
     public privilegio_dao() { }  
     public privilegio localiza(int id) throws PersistenceException
     {  
            try{
                EntityManagerFactory factory =Persistence.createEntityManagerFactory("persistencia");
                EntityManager manager = factory.createEntityManager();     
                 privilegio p= manager.find(privilegio.class,id);
                 factory.close();
                 manager.close();  
                 return p;
         }
         catch(PersistenceException pe)
         { 
             pe.printStackTrace(); 
             return null;
             
         }  
     }
 }