Is new Stack<?>[N]
equivalent to new Stack[N]
for a generic data type Stack<Item>
?
EDIT: While I understand that mixing generic types and arrays should best be avoided and that more robust solutions exist, my query still stands: widely recognized textbooks such as Algorithms, 4th Edition by Kevin Wayne and Robert Sedgewick (pg. 158) suggest using constructs like the following:
Stack<String>[] a = (Stack<String>[]) new Stack[N];
[ Turning my comment into a real answer ]
1) Mixing arrays and generic types should be avoided.
2) Instead, one can use Java Collection types, for example ArrayList when the need comes up to handle multiple "generic" objects, like in
Yes, they are equivalent, except for the return type (one is
Stack[]
, the other isStack<?>[]
).Note that
Stack[]
can be assigned toStack<String>[]
without an explicit cast (you will just get an unchecked conversion warning), whereas it is an error to assign aStack<?>[]
toStack<String>[]
without a cast.new Stack[N]
uses a raw type which is not recommended in new code.