Sorting a map by date key in Java
I'm trying to sort a map in java by date key using TreeMap. Here's my code public static void sort() { BufferedReader br; String line; String[] data; Date date ; DateFormat df = new SimpleDateFormat("dd-mm-YYY"); Map<Date,String> map = new TreeMap<Date,String>(); try { br = new BufferedReader(new FileReader( "/home/user/Desktop/train/2013-training_set.txt")); int i=0; while ((line = br.readLine()) != null) { ++i; data = line.split(":"); map.put(df.parse(data[1]), line); } System.out.println(map.size()+" i = "+i); Set st = mp.entrySet(); Iterator it = st.iterator(); while (it.hasNext()) { Map