uibinder - How to call method of @UiField field in GWT -

here classes

public class personview extends composite{      private person person;      @uifield     firstnameview firstnameview;     @uifield     lastnameview lastnameview;      public personview(person person) {         setdata(person);     }      public void setdata(person person) {         firstnameview.setdata(person.getfirstname());         lastnameview.setdata(person.getlastname());     } } public class firstnameview extends composite{          private firstname firstname;          @uifield         textbox firstnametextbox;          public firstnameview() {         }          public void setdata(firstname firstname) {             firstnametextbox.setvalue(firstname.getfirstname());         }     } public class lastnameview extends composite{          private lastname lastname;          @uifield         textbox lastnametextbox;          public lastnameview() {         }          public void setdata(lastname lastname) {             lastnametextbox.setvalue(lastname.getlastname());         }     } 

my problem when call method setdata(person), following error

java.lang.nullpointerexception: null in line `firstnameview.setdata(person.getfirstname())` 

i think @uifield firstnameview firstnameview (and lastnameview too) doesn't create object. don't understand how gwt works in case. me please resolve , set data.

@uifields "injected" when call initandbindui on uibinder instance, passing instance @uifields argument.

in other words, personview constructor should begin initializing uibinder instance , calling binder.initandbindui(this) before can call setdata().