sort arraylist of complex objects alphabetically

Question

I know that Collections.sort(myArrayList) can sort an arraylist alphabetically when they are strings, but what about when they are something more complex such as a

Answer 1

I would create an inner class implementing the Comparator interface:

public class Car {
public double horsePower;

class CarHorsePowerComparator implements Comparator {
    @Override
    public int compare(Car car1, Car car2) {
        return Integer.valueOf(car.horsePower).compareTo(Integer.valueOf(car2.horsePower))          }
    }
}

Now when you want to sort your Car list by horsePower:

List list = new ArrayList(myCars); //your Car list
Collections.sort(list, new CarHorsePowerComparator());