Cast reference of known type to an interface outside of type's hierarchy

Question

Say you have a clean class like this:

public class A {
    // Stuff
}

And a interface like this:

public interface G {
    /         


        

Answer 1

The compiler doesn't necessarily know whether or not a implements G or not.

Casting pretty much tells the compiler to take this variable, and treat it like a different type.

If you try to do an operation on the cast variable as though it implemented G(when it doesn't) you'll get a runtime error