How to upcast object contained in Java 8 Optional?

Question

Is there an efficient way to perform upcasting while using an Optional object. Here is a sample code:

class A{}
class B extends A{}

B func(){
    //do somet         


        

Answer 1

You can try using a mapping function:

Optional oa = func2().map(v -> (A) v);

Note that you don't really need to put the (A) cast there, but it makes it a little clearer what's going on.