class Simpson implements Comparable<Simpson> {

    String name;

​

    Simpson(String name) {

        this.name = name;

    }

​

    @Override

    public int compareTo(Simpson simpson) {

        return this.name.compareTo(simpson.name);

    }

}

In Java Strings, the == operator is used to check the reference of both the string objects.

Use .equals method instead:

str1.equals(str2)

        Collections.sort(marvelHeroes, new Comparator<String>() {

            @Override

            public int compare(String hero1, String hero2) {

                return hero1.compareTo(hero2);

            }

        });

​

        Collections.sort(marvelHeroes, (m1, m2) -> m1.compareTo(m2));

​

        Collections.sort(marvelHeroes, Comparator.naturalOrder());

​

       SimpsonCharacter homer = new SimpsonCharacter("Homer") {

            @Override

            public int compareTo(SimpsonCharacter simpson) {

                return this.name.length() - (simpson.name.length());

            }

        };

compare(x,y);

Returns:

    0: if (x==y)

   -1: if (x < y)

    1: if (x > y)