public class Person implements Comaparable<Person> {
  public Person(String name, int age) {
    this.name = name;
    this.age = age;
  }
  public String getName() { return this.name; }
  public int getAge() { return this.age; }
  /** Sorts Person objects by name, then age */
  public int compareTo() {
    // image a reasonable compareTo implemementation
  }
}

// Some version of Java with no Comparable (and also assuming no Comparator, either)
public class SomeService {

  public List<Person> queryPeople(boolean sort) {
    List<People> people = findPeople();
    if (sort) {
      Collections.sort(people);
    }
    return people;
  }
}