Sorting a HashMap by date

Question

In a Java class I have a method to reOrder an existing HashMap by date. The HashMap is of a type where the Object contains a field called exp

Answer 1

Use a TreeMap instead of HashMap. it will be sorted automatically on insertion.

Map< Date, Object> m = new TreeMap< Date, Object>();

Alternatively, if you have an existing HashMap and want to create a TreeMap based on it, pass it to the constructor:

Map< Date, Object> sortedMap = new TreeMap< Date, Object>(m);

Hope it will help you.