Comparator and equals()

Question

Suppose I need TreeSet with elements sorted with some domain logic. By this logic it doesn\'t matter order of some elements that doesn\'t equal so compare metho

Answer 1

Yes, as others said above, hashCode() is not secure to use here. But if you dont care about the ordering of objects that are equal in terms of o1.compareTo(o2) == 0, you could do something like:

public int compare(Foo o1, Foo o2) {
        int res = o1.compareTo(o2);
        if (res == 0 && !o1.equals(o2)) {
            return -1;
        }
        return res;
}