why methods of SimpleFormController are overridden from a Class optionally and not mandatory?

[Monica Shiralkar]

Why is SimpleFormController a Class and not an Interface. OnSubmit method is not a mandatory to implement method because it is overriden from SimpleFormController.But shouldnt this functionality be mandatory when we are using a Form? Then shouldnt this been kept in an interface and thus made mandatory to implement?

thanks.

[Nam Ha Minh]

Monica. Shiralkar wrote:Why is SimpleFormController a Class and not an Interface. OnSubmit method is not a mandatory to implement method because it is overriden from SimpleFormController.But shouldnt this functionality be mandatory when we are using a Form? Then shouldnt this been kept in an interface and thus made mandatory to implement?

thanks.

Because Spring is flexible. One can choose either to extends the SimpleFormController or not (by using XML or annotation configuration). We can write simple controller which does not tie to the framework, thus making it's easy for unit testing the controller class.