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Since primitives cant be used as generic type arguments, ex. There is nothing new or different about using a lambda with Arrays.sort(). This tutorial shows various examples of sorting an array using such methods, especially using the Comparable and Comparator interfaces. The Arrays.sort(T, Comparator) is a generic method where both the first and second parameters use the type variable. It is simply the form of Arrays.sort () that relies on a Comparator to define the order, with that Comparator implemented via a lambda.

There is nothing new or different about using a lambda with Arrays.sort (). This is how Arrays.sort() uses Comparators - the Comparator provided serves as a stand-in for relational operators.īecause Comparator is a functional interface, implementations can be provided in the form of lambdas. Because Comparator is a functional interface, implementations can be provided in the form of lambdas. However if the ArrayList is of custom object type then in such case you have two options for sorting- comparable and comparator interfaces. Moreover, Comparators allow objects to be sorted according to any chosen order, as for all practical intents and purposes the chosen Comparator implementation defines the order. ), which do not apply to most types of objects. That can be used in various ways, but in particular, it can be used to sort a sequence of such objects, with the Comparator used in place of the relational operators (. Its compare() method accepts two arguments, and reports on their relative order by returning -1 if the first argument is ordered before the second, +1 if the first is ordered after the second, or 0 if the two are equal, with respect to the ordering implemented. A Comparator is an object that answers the question of how pairs of objects of suitable type compare to each other with respect to a given ordering.