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

Your best bet will be to use a SortedMap with the Comparator interface.

Here is an example:

public SortedMap getSortedMap(Map originalMap) {
    SortedMap tmpMap = new TreeMap(new Comparator(){
        @Override
        public int compare(String key1, String key2) {
            //logic for comparing dates
        }           
    });
    tmpMap.putAll(originalMap);
    return tmpMap;
}