The natural order that Java often mentions (Natural ordering)

Natural ordering are often referred to in containers and appear with iterators.

A description was found in the API specification of the comparable interface.

(https://docs.oracle.com/javase/8/docs/api/java/lang/Comparable.html)

The natural ordering for a class C was said to being consistent with equals if and only if E1.compareto (e2) = = 0 has the same Boolean value as E1.equals (E2) for every E1 and E2 of Class C.

Note that NULL was not an instance of any class, and e.compareto (null) should throw a nullpointerexception even though E.eq Uals (NULL) returns FALSE.

That is, for any instance object E1 and E2 of Class C, the expression "E1.compareto (e2) = = 0" Returns the same Boolean value as the other expression "e1.equals (E2)".

The natural order that Java often mentions (Natural ordering)