Java 8 Lambda: Comparator

Question

I want to sort a list with Lambda:

List messagesByDeviceType = new ArrayList();      
messagesByDeviceType.sort((Message o1, Messag         


        

Answer 1

The compare() method must return an int, and it seems yours is returning a long.

You can change it this into:

Long.compare(o1.getTime(),o2.getTime())

Well explained regarding lambda comparator in the below presented video link.