Sort Dates in JavaThe sort() method that is a part of Comparator mechanism of Collection class that sorts the data in decreasing order. If we want to achieve the aim in generic while considering the boundary condition where the objects to be sorted are user-defined, we can use Comparator interface. Both ways are discussed below, where the user-defined type is also used to generate the object. There are several ways in Java for sorting things in an ArrayList by date. It can be accomplished either by using the Comparable<> interface or the Collections.sort() method; we can use any of the following ways.
1. Comparator interfaceJava Programs to sort elements of ArrayList by Date using Comparator interface. SortDate1.java Output: Dates sorted in Ascending Order 1998-02-20 1999-04-26 2019-06-24 2021-05-14 Let's see another example. SortDate2.java Output: Dates sorted in Descending Order 2021-05-14 2019-06-24 1999-04-26 1998-02-20 2. sort() methodJava Programs to sort elements of ArrayList by Date using Collections.sort() method SortDate3.java Output: Dates Object before sorting: 2020-03-25 2019-01-27 2020-03-26 2020-02-26 Dates Object after sorting: 2019-01-27 2020-02-26 2020-03-25 2020-03-26 SortDate4.java Output: ---> Date & Time Object List Before Sort (MM/dd/yyyy '@'hh:mm a) 05/12/2012 @05:16 AM 03/23/2014 @11:26 AM 02/13/2011 @09:36 AM 11/12/2013 @05:16 AM 08/11/2017 @09:26 PM 09/05/2016 @07:36 PM ---> Date & Time Object List After Sort (MM/dd/yyyy '@'hh:mm a) 02/13/2011 @09:36 AM 05/12/2012 @05:16 AM 11/12/2013 @05:16 AM 03/23/2014 @11:26 AM 09/05/2016 @07:36 PM 08/11/2017 @09:26 PM ---> Date & Time List Before Sort (MM/dd/yyyy '@'hh:mm a) 01/21/2014 @03:13 PM 01/21/2011 @04:37 PM 01/21/2012 @10:41 AM 01/21/2013 @10:48 AM 01/22/2015 @06:16 AM 01/22/2013 @06:19 AM 01/21/2018 @05:19 PM 01/21/2013 @05:19 PM ---> Date & Time List After Sort (MM/dd/yyyy '@'hh:mm a) 01/21/2011 @04:37 PM 01/21/2012 @10:41 AM 01/21/2013 @10:48 AM 01/21/2013 @05:19 PM 01/22/2013 @06:19 AM 01/21/2014 @03:13 PM 01/22/2015 @06:16 AM 01/21/2018 @05:19 PM
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