Sorting array lists in Java

I have finished class Here, iris is another class with certain properties

public class Helper {

    Iris iris;
    double distance;

    public Helper(Iris iris,double distance) {
        this.iris = iris;
        this.distance = distance;
    }
}

I want to sort the array list (i.e. list < helper > helperlist) in descending order according to the distance parameter I wrote the following method, but it didn't work

public void sort(){
for(int k=0; k < helperList.size(); k++)
        {
            double distance = helperList.get(k).distance; 

             for(int l=0; l < helperList.size(); L++)
             {
                 Helper temp = helperList.get(l);
                 if( distance < temp.distance )
                 {
                     helperList.set(l,helperList.get(k));
                     helperList.set(k,temp);
                 }
            }
        }
}

Can anyone propose a solution?

Solution

Why not let the helper class implement the comparable interface and then use the built-in sorting method provided by the collections class

Collections.sort(helperList)

I think this will solve the problem In addition, this sort method is very stable

http://docs.oracle.com/javase/7/docs/api/java/util/Collections.html#sort%28java.util.List%29

http://docs.oracle.com/javase/7/docs/api/java/lang/Comparable.html

Implement the comparable interface:

public class Helper implements Comparable{

    Iris iris;
    double distance;

    public Helper(Iris iris,double distance) {
        this.iris = iris;
        this.distance = distance;
    }

    public int compareTo(Helper other) {
        return new Double(this.distance).compareTo(new Double(other.distance));

    }
}