wildcard unknown type element

[Edgar Trania]

ArrayList<Number> nl = new ArrayList<Number>();
		nl.add(1);
		nl.add(1.5);
		ArrayList<? extends Number> nl2 = nl;

		for(Object n: nl2)
			System.out.println(n);

		for(Number n: (Number) nl2)
			System.out.println(n);

line 6 can produce output
but in line 9 caused compile error incovertible type

[Jeff Verdegan]

This line:

for(Number n: (Number) nl2)

says "cast nl2 to a number", not "cast the elements of nl2 to numbers." You can't cast a List to a number. And you don't need the cast here because nl2 is already ArrayList<Number>, so just

for(Number n: nl2)

is fine.

And in this particular case, since you're just calling println(n) you could have just treated them as Object anyway. (I know that's just a placeholder--just teasing you a little )