final Map<Integer, List<Student>> map = students.stream()
        .collect(Collectors.groupingBy(Student::getGender));

for (Map.Entry<Integer, List<Student>> entry : map.entrySet()) {
      map.get(entry.getKey()) // get the list
          .stream()
          .sorted()
          .forEach(student -> System.out.println(student.getName()));
      System.out.println();
}