Your solution is OK, but has the downside of creating a new Optional instance.
An alternative is to write a utility method, in which you can suppress the warning just once:
@SuppressWarnings("unchecked") // Safe covariant cast.
static Optional upcast(Optional opt) {
return (Optional) opt;
}
and then just use this in all the places without warnings.
But better (if you have the control to do so) is to fix the place where you need an Optional to accept an Optional.
