Lo, on Friday, January 4, David Jardine did write:
> On Thu, Jan 03, 2002 at 05:34:00PM -0600, Richard Cobbe wrote:
> >
> > Yes, it *is* types. Remember the definition of type-safety:
> >
> > If an expression E is determined at compile time to have type T,
> > then evaluating E will have one of two results:
> >
> > 1) The value of E is a valid object of type T and not just some
> > random collection of bits we're misinterpreting as a T.
> > 2) a well-defined runtime error occurs (e.g., Java's
> > ArrayBoundsException).
> >
> An ArrayBoundsException is not a question of type in Java. An
> array of two chars is exactly the same type as an array of two
> thousand chars. A two-dimensional array of chars, on the other
> hand, is a different type from a three-dimensional one.
Consider the Java declaration
int a[]
The issue above is not the type of a, but rather the type of a[45].
The compiler determines that a[45] has type int---try passing it as an
argument to a method that expects a string, and you'll get a compilation
error, regardless of the actual number of elements in a.
Since the compiler has determined a[45] to have type int, then
evaluating that expression better darned well produce a real-live int.
If it can't (because a only has 4 elements), then, to preserve
type-safety, Java signals an error.
Richard
