There is some crap like that still kicking around. Why you need to create a Comparator class to provide a single function for sorting or filtering out duplicate

There is some crap like that still kicking around. Why you need to create a Comparator class to provide a single function for sorting or filtering out duplicate items is silly, when a Func <T, bool> lambda would work? Because it's the old way of doing things, back in the 1/2 era, when delegates didn't have all the syntax sugar to make them painless.