Q:

Sort a Map in Java is not working

I am trying to sort a TreeMap (having Double as a value and Integer value as a key) using Comparator interface but it's not working. 
// Create a tree map
        TreeMap tm = new TreeMap();
        // Put elements to the map
        tm.put(1, new Double(3434.34));
        tm.put(0, new Double(123.22));
        tm.put(4, new Double(1378.00));
        tm.put(2, new Double(99.22));
        tm.put(3, new Double(-19.08));
        List<Map. Entry> valueList = new ArrayList(tm.entrySet());

        // Collections.sort(valueList, new Sort());

        Collections.sort(valueList, new Sort());

        HashMap sortedMap = new HashMap();

        // Get an iterator
        Iterator<Map. Entry> i = valueList.iterator();

        // Display elements
        while (i.hasNext()) {
            Map. Entry object = i.next();
            sortedMap.put(object.getKey(), object.getValue());
        }
        List sortedList = new ArrayList(sortedMap.entrySet());
        Iterator<Map. Entry> iterator = sortedList.iterator();
        while (iterator.hasNext()) {
            Map. Entry entry = iterator.next();
            System.out.println("Value " + entry.getValue() + "\n");
        }

The following is my Comparator class
public class Sort implements Comparator<Map. Entry> {

    @Override
    public int compare(Map. Entry o1, Map. Entry o2) {
        // TODO Auto-generated method stub
        double valueOne = (Double) o1.getValue();
        double valueTwo = (Double) o2.getValue();

        int returnValue =
            valueOne > valueTwo ?  -1 : (valueOne == valueTwo ?  0 : 1);

        return (valueOne > valueTwo ?  -1 : (valueOne == valueTwo ?  0 : 1));
    }

}

But i am getting the following output
Value 123.22

Value 3434.34

Value 99.22

Value -19.08

Value 1378.0

Edited Part

public int compare(Map. Entry o1, Map. Entry o2) {
        // TODO Auto-generated method stub
        double valueOne = ((Double) o1.getValue()).doubleValue();
        double valueTwo = ((Double) o2.getValue()).doubleValue();

        int returnValue =
            valueOne > valueTwo ?  -1 : (valueOne == valueTwo ?  0 : 1);

        return (valueOne > valueTwo ?  -1 : (valueOne == valueTwo ?  0 : 1));
    }

A:

HashMap is intrinsically unordered. 
Instead, you can create a TreeMap with your comparator in the first place. 

A:

Adding to what others have already suggested, try this:
import java.util. ArrayList;
import java.util. Collections;
import java.util. Comparator;
import java.util. Iterator;
import java.util. List;
import java.util. Map;
import java.util. Map. Entry;
import java.util. TreeMap;

public class SortDemo
{
  public class Sort implements Comparator<Map. Entry>
  {
    public int compare(Entry o1, Entry o2)
    {
      Double valueOne = (Double) o1.getValue();
      Double valueTwo = (Double) o2.getValue();
      return (int) Math.signum(valueOne.compareTo(valueTwo));
    }
  }

  public static void main(String[] args)
  {
    new SortDemo().foo();
  }

  void foo()
  {
    TreeMap tm = new TreeMap();
    tm.put(1, new Double(3434.34));
    tm.put(0, new Double(123.22));
    tm.put(4, new Double(1378.00));
    tm.put(2, new Double(99.22));
    tm.put(3, new Double(-19.08));

    List<Map. Entry> valueList = new ArrayList(tm.entrySet());
    Collections.sort(valueList, new Sort());

    Iterator<Map. Entry> iterator = valueList.iterator();
    while (iterator.hasNext())
    {
      Map. Entry entry = iterator.next();
      System.out.println("Value: " + entry.getValue());
    }
  }
}

