Sorting Collections with Java Lambdas

In Java, the Comparator class is used for sorting collections. In the following examples, we will sort a list of players based on name, surname, name length and last name letter. We will first sort them as we did before, using anonymous inner classes, and then reduce our code using lambda expressions.

In the first example, we will sort our list by name. Using the old way, this looks like this:

String[] players = {"Avijit", "Chintu", "Akshay", "Santosh", "Ritesh", "Avisek", "Krushna", "Surya", "Rudra", "Biswajit"};

// Sort players by name using anonymous innerclass

Arrays.sort(players, new Comparator<String>() {

       @Override

       public int compare(String s1, String s2) {

              return (s1.compareTo(s2));

       }

});

With lambdas, the same thing can be achieved like this:

// Sort players by name using lambda expression

Comparator<String> sortByName = (String s1, String s2) -> (s1.compareTo(s2));

Arrays.sort(players, sortByName);

// or this

Arrays.sort(players, (String s1, String s2) -> (s1.compareTo(s2)));