NativeSelect setNullSelectionAllowed(false) not working in 7.1.10

Vaadin 6 / 7 / 8
1

Hi ,

I am facing issue to set non blank value in NativeSelect component .
i used below code , but no hopes.

NativeSelect typeSlt= new NativeSelect();
typeSlt.setNullSelectionAllowed(false);

Advace thansk.