Sorting arraylist of objects based on the date time

Question

I have two arraylists that consist of the datetime objects and merging both the list using.

list1.addAll(list2);

I want to now sort this arraylist on the order of the date time object that the arraylist consists of. Can anyone guide me how to sort this arraylist.

• Cephron: @naveen -- it's tagged with java
• Boris Strandjev: Collections.sort(list1); should do the trick for you.
• Cephron: Possible dupe of stackoverflow.com/questions/5927109/…

Answer 1

If you meant they have Java Date object. You can just do Collections#sort()

Answer 2

ArrayList<Date> myDates = new ArrayList<>();
// populate the List... 
Collections.sort(myDates);

If you are using Joda Time Date time, this is done the same way, since those classes usually implement Comparable.

• JB Nizet: No need for a custom comparator.
• Charles Wood: Almost the same? What's the difference?

Answer 3

You can define your comparator for the objects of the arraylist, like if I am using objects having structure

and then you can use, sort method directly.