Sorting an ArrayList of Objects by Last name and firstname in Java

Question

I have an arrayList of different types of players based on sports. I need to sort the list of players in the arrayList by last name to start. If 2 players have the same la

Answer 1

    //requires java@8
    //class Person { String fName; String lName; int id}

    List list = new ArrayList<>();
    Person p1 = new Person();
    p1.setfName("a");
    p1.setlName("x");
    list.add(p1 );

    Person p4 = new Person();
    p4.setfName("b");
    p4.setlName("z");
    list.add(p4);

    Person p3 = new Person();
    p3.setfName("a");
    p3.setlName("z");
    list.add(p3);

    Person p2 = new Person();
    p2.setfName("a");
    p2.setlName("y");
    list.add(p2);

    //sort by a single field
    Collections.sort(list, (o1,o2) ->  o1.getfName().compareTo(o2.getfName()));

    //sort by multiple cascading comparator.
    Collections.sort(list, Comparator.comparing(Person::getfName).thenComparing(Person::getlName));
    list.forEach( System.out::println);

    //output
    //Person [fName=a, lName=x, id=null]
    //Person [fName=a, lName=y, id=null]
    //Person [fName=a, lName=z, id=null]
    //Person [fName=b, lName=z, id=null]