Question

I want to make a class usable in SortedSet | SortedMap.

class MyClass implements Comparable<MyClass>{
  // the only thing relevant to comparisons:
  private final String name;

  //...
}

The class’ instances must be sorted by their name property.
However, I don’t want equally named instances to be considered as equal.

So a SortedSet content would look like a, a, a, b, c.
(Normally, SortedSet would only allow a, b, c)

First of all: is this (philosophically) consistent?

If so, do I have to expect unpredictable behavior, when I don’t
override equals(...) and hashCode()?

Edit:
I am sorry, my question seems inconsistent:
I want to put multiple “equal” values inside a set, which doesn’t allow this
by concept.
So, please don’t reply to my question anymore.
Thanks to all who already replied.

Answer 1

Let me ask you a question: does it make sense to have a.compareTo(b) return 0 and a.equals(b) return false?

I would use a Comparator<MyClass> instead. This is why all SortedMap/SortedSet implementations that I know of allow you to pass in a Comparator at creation.