Sort an ArrayList base on multiple attributes using java/grails

I have an ArrayList of object. The object contain attributes name and classValue. So I want to sort the objects on the classValue, and for all objects in the same classValue I want to sort them on name.

---

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;

/**
 *
 * @author Pritom Kumar
 */
public class MapSort {
    public static void main(String[] args) {
        MapSort mapSort = new MapSort();
        mapSort.sort();
    }
    
    public void sort() {
        List keys = new ArrayList();
        HashMap map1 = new HashMap();
        map1.put("name", "Pritom");
        map1.put("classValue", 5);
        keys.add(map1);
        
        HashMap map2 = new HashMap();
        map2.put("name", "Bappi Lahiri");
        map2.put("classValue", 10);
        keys.add(map2);
        
        HashMap map3 = new HashMap();
        map3.put("name", "Ashok Kumar");
        map3.put("classValue", 5);
        keys.add(map3);

        Collections.sort(keys,
            new Comparator() {
                public int compare(Object left, Object right) {
                    HashMap leftMap = (HashMap) left;
                    HashMap rightMap = (HashMap) right;
                    Integer classValue1 = Integer.parseInt(leftMap.get("classValue").toString());
                    Integer classValue2 = Integer.parseInt(rightMap.get("classValue").toString());
                    int comp = classValue1.compareTo(classValue2);
                    return comp == 0 ? leftMap.get("name").toString().compareTo(rightMap.get("name").toString()) : comp;
                }
            });

        //List the values
        Object[] keyList = keys.toArray();
        for(Integer index = 0; index < keyList.length; index++) {
            System.out.println(keyList[index]);
        }
    }
}

And the output is as following. At first sorts by classValue and then by name.

{name=Ashok Kumar, classValue=5}
{name=Pritom, classValue=5}
{name=Bappi Lahiri, classValue=10}