How to sort by two fields in Java?

Question

I have array of objects person (int age; String name;).

How can I sort this array alphabetically by name and then by age?

Which algorithm would

Answer 1

Have your person class implement Comparable and then implement the compareTo method, for instance:

public int compareTo(Person o) {
    int result = name.compareToIgnoreCase(o.name);
    if(result==0) {
        return Integer.valueOf(age).compareTo(o.age);
    }
    else {
        return result;
    }
}

That will sort first by name (case insensitively) and then by age. You can then run Arrays.sort() or Collections.sort() on the collection or array of Person objects.