Sort a HashMap by key !!

Sorting a HashMap by key in Java:

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class SortMapByKey {
public static void main(String[] args) {
Map<String, Integer> map = new HashMap<String, Integer>();
map.put("z", 1);
map.put("q", 2);
map.put("p", 3);
map.put("s", 4);
map.put("o", 5);
System.out.println(map);
Set<Entry<String, Integer>> entrySet = map.entrySet();
List<Entry<String, Integer>> lists = new ArrayList<Entry<String, Integer>>(entrySet);

Collections.sort(lists, new Comparator<Entry<String, Integer>>() {
@Override
public int compare(Entry<String, Integer> o1, Entry<String, Integer> o2) {
return (o1.getKey()).compareTo(o2.getKey());
}
});
System.out.println("--------------------");
for (Map.Entry<String, Integer> entry : lists) {
System.out.println(entry.getKey() + " :: " + entry.getValue());
}
}
}

Output: 
{p=3, q=2, s=4, z=1, o=5}
--------------------
o :: 5
p :: 3
q :: 2
s :: 4
z :: 1