Question

So I’m working on a comparator problem and I can’t figure out why the Array.sort in this first class is giving me the error of:

The method sort(T[], Comparator) in the type Arrays is not applicable for the arguments (ArrayList, CalorieComparator)

Restaurant Class:

import java.util.ArrayList;
import java.util.List;
import java.util.Arrays;

public class Restaurant {
    private ArrayList<Edible> elist;

    public Restaurant() {
    }

    public void addEdibleItem(Edible item){
        elist.add(item);
    }

    public List<Edible> orderByCalories(){
        Arrays.sort(elist, new CalorieComparator());
    }

CalorieComparator class:

import java.util.Comparator;
public class CalorieComparator implements Comparator {

    public int compare(Object o1, Object o2){
        Edible thisfood = (Edible)o1;
        Edible otherfood = (Edible)o2;
        if(thisfood.getCalories() > otherfood.getCalories())
            return 1;
        else if (thisfood.getCalories() < otherfood.getCalories())
            return -1;
        else 
            return 0;
    }
}

Answer 1

An ArrayList is different from a Java array; since you’re using a List, Arrays.sort won’t help you here.

Consider Collections.sort instead.