What is the difference between these two ways of casting in Java?

Question

What is the difference between these two ways of casting in Java?

1. (CastingClass) objectToCast;

2. CastingClass.class.cast(objectToCast);

The source of Class#cast(Object) is as follows:

public T cast(Object obj) {
if (obj != null && !isInstance(obj))
    throw new ClassCastException();
return (T) obj;
}

So, cast is basically a generic wrapper of the cast operation, but I still don't understand why you would need a method for it.

Answer 1

You can only use the first form for statically linked classes.

In many cases that's not enough - for example, you may have obtained class instance using reflection or it was passed to your method as parameter; hence the second form.

Answer 2

Because you cannot just write (T)objectToCast, when T is a generic type parameter (due to type erasure). Java compiler will let you do that, but T will be treated as Object there, so the cast will always succeed, even if the object you're casting isn't really an instance of T.