Si usas listas en tus aplicaciones de Android, el siguiente code snippet sirve para Ordenar items de objetos List en Java, dependiendo del campo se ordenarán.

Clase Person.java

public class Person {
    String gender;
    String name;
    int age;
    double height;
    double weight;

   public Person(String gender, String name, int age, double height, double weight) {
        this.gender = gender;
        this.name = name;
        this.age = age;
        this.height = height;
        this.weight = weight;
   }

//Getters
   public String getGender() {
       return this.gender;
   }
   public String getName() {
       return this.name;
   }
   public int getAge() {
       return this.age;
   }
   public double getHeight() {
       return this.height;
   }
   public double getWeight() {
       return this.weight;
   }
}

Llenar contenido de muestra

List people = new ArrayList<>();
people.add(new Person("F","Alice", 15, 160, 48));
people.add(new Person("F","Karen", 18, 140, 45)); 
people.add(new Person("MALE","Bob", 8, 90, 30)); 
people.add(new Person("MALE","John", 40, 180, 78)); 

Función para ordenar

class SortPersonaByAge implements Comparator<Person> {

    @Override
    public int compare(Person o1, Person o2) {
        return o1.age - o2.age;
    }

}

Ordenar la lista Ascendente

Collections.sort(people,new SortPersonaByAge());

Ordenar la lista Descendente

Collections.sort(people, Collections.reverseOrder(new SortPersonaByAge()));