How to get inverse of a comparator in java

Question

In a method I receive a generic object E extends Comparable as an argument. Now i want to create two priority queues.One which uses the comparato

Answer 1

Your object E extends java.lang.Comparable, but it is not a java.util.Comparator.

Create your first queue w/o a Comparator and you'll get the ordering in your compareTo function, then create a java.util.Comparator that does the comparison in reverse (just call a.compareTo(b) and then negate the result) and create your second queue with that comparator.