IllegalArgumentException: Person[ id=null ] is not a known entity type.?

Ich arbeite gerad an einem Project mit JSF, EclipseLink. Wenn ich mein Formular abschicke rufe ich

       public String save() {
              PersonDAO dao = new PersonDAO();

              dao.create(user);
              return "/registry.xhtml";
       }

Die DAO sieht hierbei wie folgt aus

public class PersonDAO extends GenericDAO<Person> {}
public class GenericDAO<T> implements AbstractBasicDAO<T> {
       /**
        * the entity manager
        * 
        * @var      EntityManager
        */
       protected EntityManager em;
       
       /**
        * this is the class type to handle
        * 
        * @var      Class<T>
        */
       private Class<T> type;

       /**
        * default constructor
        */
       public GenericDAO() {
              Type              t  = getClass().getGenericSuperclass();
              ParameterizedType pt = (ParameterizedType) t;
              
              type = (Class) pt.getActualTypeArguments()[0];              
              this.em = EntityManagerUtil.getEntityManager();
       }
       
       /**
        * Make an instance managed and persistent.
        * 
        * @param    t   the entity to store
        * @return       the stored entity
        */
       @Override
       public T create(final T t) {
                this.em.persist(t);
                return t;
       }
       
       /**
        * Find by a spezified primary key.
        * 
        * @param    id  the id to find
        * @return       the found entity
        */ 
        @Override
        public T find(final Object id) {
               return (T) this.em.find(type, id);
        }
        
       /**
        * Find all entites by an given query
        * 
        * @param    sql     the sql query
        * @return   the found entity
        */         
        @Override
        public List find(String sql) {
               return em.createQuery(sql).getResultList();
        }        
        
       /**
        * Merge the state of the given entity into the current persistence context.
        * 
        * @param    t   the entity to store
        * @return       the stored entity
        */       
       @Override
       public T update(final T t) {
              return this.em.merge(t);    
       }
       
       /**
        * delete an object by his pramary key
        * 
        * @param    id   the priamary key to delete
        */              
       @Override
       public void delete(final Object id) {
              this.em.remove(this.em.getReference(type, id));
       }

}

Der EntityManager sieht wie folgt aus

public class EntityManagerUtil {
       final static org.apache.log4j.Logger logger = Logger.getLogger(EntityManagerUtil.class);
       
       /**
	* the entity manager
        * 
        * @var  EntityManager
	*/
       private static EntityManager entityManager;

       /**
        * default constructor
        *
        * @throw    ExceptionInInitializerError
        */
       static {
              try {
                  EntityManagerFactory factory = Persistence.createEntityManagerFactory("JAPPU");
                  entityManager = factory.createEntityManager();
              } catch( Throwable ex ) {
                    logger.error("Error on EntityManager inializing", ex); 
                    throw new IllegalStateException(ex);
              }               
       }
       
       /**
        * get the EntityManager
        *
        * @return   EntityManager
        */
       public static EntityManager getEntityManager() {
              return entityManager;
       }
}

Die Entity sieht wie folgt aus

package com.abado.jap.entities.user;

import java.io.Serializable;
import java.util.Collection;
import java.util.Date;
import javax.persistence.*;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlTransient;

@Entity
@Table(name="person")
public class Person implements Serializable {       
       @Id
       @GeneratedValue(strategy = GenerationType.AUTO)
       @Basic(optional = false)
       @Column(name = "id")
       private Long id;

       @OneToMany(mappedBy = "createdBy")
       private Collection<Person> creators;
       @JoinColumn(name = "created_by", referencedColumnName = "id")
       @ManyToOne
       private Person createdBy;
              
       @Column(name = "created_at")
       @Temporal(TemporalType.TIMESTAMP)
       private Date        created_at;
       
       @OneToMany(mappedBy = "modifiedBy")
       private Collection<Person> modifiers;
       @JoinColumn(name = "modified_by", referencedColumnName = "id")
       @ManyToOne
       private Person modifiedBy;
       
       @Column(name = "modified_at")              
       @Temporal(TemporalType.TIMESTAMP)       
       private Date        modified_at;

       @Basic(optional = false)
       @NotNull
       @Column(name = "block")
       private boolean block;
    
       @Size(max = 255)
       @Column(name = "active_code")
       private String activeCode;
       
       @Column(name = "gender")              
       private EGender     gender;
       
       @Column(name = "firstname")                     
       private String      firstname;
       
       @Column(name = "lastname")                            
       private String      lastname;
       
       @Column(name = "birthdate")  
       @Temporal(TemporalType.TIMESTAMP)    
       private Date        birthdate;
       
       @Column(name = "email")                                          
       private String      email;
       
       @Column(name = "password")                                                 
       private String      password;

       /**
        * default constructor
        */
       public Person() {
       }

       //--- GETTER / SETTER
       public Long getId() {
              return id;
       }

       public void setId(Long id) {
              this.id = id;
       }

       public Person getCreatedby() {
              return createdBy;
       }

       public void setCreatedBy(Person created_by) {
              this.createdBy = created_by;
       }

       @XmlTransient
       public Collection<Person> getCreators() {
              return creators;
       }

       public void setCreators(Collection<Person> creators) {
              this.creators = creators;
       }

       public Date getCreatedAt() {
              return created_at;
       }

       public void setCreatedAt(Date created_at) {
              this.created_at = created_at;
       }

       public Person getModifiedBy() {
              return modifiedBy;
       }

       public void setModified_by(Person modified_by) {
              this.modifiedBy = modified_by;
       }
    
       @XmlTransient
       public Collection<Person> getModifiers() {
              return modifiers;
       }

       public void setModifiers(Collection<Person> modifiers) {
              this.modifiers = modifiers;
       }
    
       public Date getModified_at() {
              return modified_at;
       }

       public void setModified_at(Date modified_at) {
              this.modified_at = modified_at;
       }
       
       public boolean getBlock() {
              return block;
       }

       public void setBlock(boolean block) {
              this.block = block;
       }

       public String getActiveCode() {
              return activeCode;
       }

       public void setActiveCode(String activeCode) {
              this.activeCode = activeCode;
       }
    
       public EGender getGender() {
              return gender;
       }

       public void setGender(EGender gender) {
              this.gender = gender;
       }

       public String getFirstname() {
              return firstname;
       }

       public void setFirstname(String firstname) {
              this.firstname = firstname;
       }

       public String getLastname() {
              return lastname;
       }

       public void setLastname(String lastname) {
              this.lastname = lastname;
       }

       public Date getBirthdate() {
              return birthdate;
       }

       public void setBirthdate(Date birthdate) {
              this.birthdate = birthdate;
       }

       public String getEmail() {
              return email;
       }

       public void setEmail(String email) {
              this.email = email;
       }

       public String getPassword() {
              return password;
       }

       public void setPassword(String password) {
              this.password = password;
       }       
       
       /**
        * 
        * @return 
        */
       @Override
       public int hashCode() {
              int hash = 0;
              hash += (id != null ? id.hashCode() : 0);
              return hash;
       }

       /**
        * 
        * @param object
        * @return 
        */
       @Override
       public boolean equals(Object object) {
              // TODO: Warning - this method won't work in the case the id fields are not set
              if (!(object instanceof Person)) {
                 return false;
              }
              
              Person other = (Person) object;
              if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
                 return false;
              }
  
              return true;
       }

       /**
        * 
        * @return 
        */
       @Override
       public String toString() {
              return "com.abado.jap.entities.user.Person[ id=" + id + " ]";
       }
}

Die persistence.xml

<?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="JAPPU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>com.abado.jap.entities.user.Person</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties>
      <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/jap?zeroDateTimeBehavior=convertToNull"/>
      <property name="javax.persistence.jdbc.user" value="root"/>
      <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
      <property name="javax.persistence.jdbc.password" value=""/>
      <property name="javax.persistence.schema-generation.database.action" value="create"/>
    </properties>
  </persistence-unit>
</persistence>

Wenn ich jetzt allerdings das Formular abschicke über die obige save-Methode
wird mir ausgeaben


javax.faces.el.EvaluationException: java.lang.IllegalArgumentException: Object: com.abado.jap.entities.user.Person[ id=null ] is not a known entity type.
	at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
	at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
	at javax.faces.component.UICommand.broadcast(UICommand.java:315)
	at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
	at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
	at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
	at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
	at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
	at javax.faces.webapp.FacesServlet.service(FacesServlet.java:646)
	at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
	at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
	at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:415)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:282)
	at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
	at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:201)
	at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:175)
	at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
	at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:284)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:201)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:133)
	at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:112)
	at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
	at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:561)
	at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
	at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
	at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
	at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: Object: com.abado.jap.entities.user.Person[ id=null ] is not a known entity type.
	at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.registerNewObjectForPersist(UnitOfWorkImpl.java:4228)
	at org.eclipse.persistence.internal.jpa.EntityManagerImpl.persist(EntityManagerImpl.java:496)
	at com.abado.jap.utils.database.impl.GenericDAO.create(GenericDAO.java:52)
	at com.abado.jap.services.UserService.save(UserService.java:89)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at com.sun.el.parser.AstValue.invoke(AstValue.java:289)
	at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
	at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
	at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
	... 36 more

Weis einer von euch was hier gerad schief läuft?