Java Comparator.comparing not comparing?

Question

Following this question about sorting a list by another list, I tried to do the same thing - but from some reason it doesn\'t work for me. What am I missing?

Answer 1

The Comparator you are supplying calls indexOf for every num passed. The returned values are -1 on all calls, so the order is preserverd as-is.

You need to sort natural.

Sorting by another list of Double should be possible, but unnecessarily complicated, it would be simpler to provide a custom Object which sorts as desired.