Cannot cast from ActionForm to StudentForm

807603

Hi All,
I am getting this Eroor


Cannot cast from ActionForm to StudentForm

public ActionForward execute(ActionMapping mapping,
	                                 ActionForm form,
	                                 HttpServletRequest request,
	                                 HttpServletResponse response)
	        throws Exception {
	        StudentService service = new StudentService();
	        StudentForm studentForm = (StudentForm) form; //Error is shown here...
	        StudentDTO studentDTO = new StudentDTO();
	        BeanUtils.copyProperties( studentDTO, studentForm );
	        service.insertStudent( studentDTO );
	        request.setAttribute("employee",studentDTO);
	        return (mapping.findForward("success"));
	    }

Any help would be greatly appreciated.

Thanks
AS

796447

Ok, so form must not be a StudentForm object. Just like you can't do this:
Object o = new Object();
String s = (String) o;

What made you think that the object passed to that method really is a StudentForm object?

807603

Ok, so form must not be a StudentForm object. Just
like you can't do this:
Object o = new Object();
String s = (String) o;

What made you think that the object passed to that
method really is a StudentForm object?

Thanks for the reply.I dont quite understand what u mean .........
hopefully u explain in more detail

AS

796447

Are you under the impression that you can just cast from any object type to another? You can't. So unless the actual object type passed to that method really is a StudentForm object (or a subclass of StudentForm), you can't just willy-nilly cast it and expect it to work.

807603

Are you under the impression that you can just cast
from any object type to another? You can't. So unless
the actual object type passed to that method really
is a StudentForm object (or a subclass of
StudentForm), you can't just willy-nilly cast it and
expect it to work.

Thanks for the reply again

I think i am getting what u r saying here....

StudentForm is a subclass of Action, so i guess it is the actual object type StudentForm, let me know whether i am right with this, and dont be harsh

Thanks
AS

796447

StudentForm is a subclass of Action, so i guess it is
the actual object type StudentForm, let me know
whether i am right with this, and dont be harsh

Just because StudentForm is a subclass of Action doesn't mean the actual object passed is a StudentForm.
class Action { ... }
class StudentForm extends Action { ... }
Action x = new Action();
StudentForm y = (StudentForm) x; // can't do this - you (or whatever on your behalf) didn't actually create a StudentForm object.

If you want to see what was actually passed to that method, do this:
System.out.println("form is a: " + form.getClass());
before that line where you're trying to cast it. Then examine the output and you'll see what kind of object was actually passed in.

796447

(and you must have meant ActionForm, not Action - so adjust my reply accordingly)