Encountered NullPointerException which useing a customsized DataTableDataModel and Rich:extendedDataTable Data

[hantsy]

The action code is like the following...
@Name("myAction")
@Scope(ScopeType.CONVERSATION)
public class MyAction {

private ExtendedTableDataModel<Addressee> addresseeDataModel;
//getters and setters
     @In("entityManager")
     private EntityManager em;

@SuppressWarnings("serial")
public void createAddresseeDataModel() {
  this.addresseeDataModel = new ExtendedTableDataModel<Addressee>(new DataProvider<Addresee>(){

//in the implemetation method... I use em for pagination implmetation...but it caused the NPE....


});
}
}

I call createAddresseeDataModel in @Begin method and getAddresseeDataModel, but got  a NUllPointerException in DataProvider implemetation...It seems it can not found the injected EntityManager in the action class....

Any help is welcome....

[hantsy]

@Name("myAction") 
@Scope(ScopeType.CONVERSATION) 
public class MyAction { 
private ExtendedTableDataModel<MyObject> dataModel; 
//getters and setters 

@In("entityManager") 
private EntityManager em; 

@SuppressWarnings("serial") 

public void createAddresseeDataModel() { 

this.dataModel= new ExtendedTableDataModel<Addressee>(
new DataProvider<Addresee>(){ 
//in the implemetation method... I use em for pagination implmetation...but it caused the NPE.... 
});
 } 
}