public static <T extends Comparable<? super T>> void sort(List<T> list)

This declaration says, that argument to sort() method must be of a type List<T>,?
where T could be any type that implements Comparable<? super T> (sort requires compareTo method defined in Comparable to compare elements of list)
Comparable<? super T> means that type ? passed to Comparable could be T or any supertype of T.?

Consider this code:?

class A implements Comparable<A>{private int i = 0; A(int x){i = x;}@Overridepublic int compareTo(A o) {return i - o.i;}public String toString(){return ""+i;}}class B extends A{B(int x){super(x + 10);}//we don't override compareTo}public class Test {public static void main(String[] args){List<B> list = new ArrayList<B>();list.add(new B(3));list.add(new B(1));list.add(new B(4));list.add(new B(2));Collections.sort(list);//public static <T extends Comparable<? super T>> void sort(List<T> list)1for(B x : list){System.out.println(x);}}}

?

Class B doesn't implement Comparable<B> (and doesn't define it's own compareTo(B b) method).?
Class B inherits compareTo(A x) method from class B (we can say that it implements Comparamble<A>).?
And sort(List<B>) compiles fine, it is conforming with declaration: public static <B extends Comparable<? super B>> void sort(List<B> list)