Java generics wildcards use

Question

I am learning Java and am puzzled as to the difference between the two following definitions:

public static <T extends Object & Comparable<? super T>>
    T max(List<? extends T> list, int begin, int end) {
   ...
}

(taken from the answer to exercise 8 in the oracle java tutorial: Tutorial) and

public static <T extends Comparable<T>> 
    T max (List<T> list, int begin, int end) {
  ...
}

Depends. Without context yes, but `Collections.max(Collection extends T> coll)` in the official API uses `Object &` as part of its signature to preserve binary compatibility. So it's not always meaningless. — Alexis C., Oct 26 '15 at 14:06

score 0 · Answer 1 · edited May 23 '17 at 12:14

0

Here, have a look at this thread:

You should see the difference between the two then. Basically the former is more flexible in what you can use as T.

edited May 23 '17 at 12:14

Community

answered Oct 26 '15 at 14:17

voiDnyx

1 Answers1