The code snippet can be plugged in to any java code, to sort the defined map in ascending order
public class NewClass1 { public static void main(String[] args) throws IOException { MapnumMap = new HashMap (); numMap.put("Key1", new ArrayList(Arrays.asList("K1V1", "K1V2", "K1V3"))); numMap.put("Key2", new ArrayList(Arrays.asList("K2V1", "K2V2", "K2V3"))); numMap.put("Key3", new ArrayList(Arrays.asList("K3V3", "K3V2", "K3V3"))); numMap.put("Key4", new ArrayList(Arrays.asList("K4V1", "K4V2", "K4V3"))); /* Sort map in ascending order */ Map sortedMap = new TreeMap (numMap); Iterator itr = sortedMap.entrySet().iterator(); System.out.println("In Ascending Order: "); /* Print map contents */ while (itr.hasNext()) { Map.Entry keyValue = (Map.Entry) itr.next(); System.out.println("Key: " + keyValue.getKey()); List value = (List) keyValue.getValue(); for (int i = 0; i < value.size(); i++) { if (value != null) { if (value.get(i) != null) { System.out.println("Value: " + value.get(i)); } } } } } }