How to Sort Date in ArrayList in Java [duplicate]

Question

I have a Map< String,ArrayList< BonusEntity > > Here key is EmpId of Employee and key will contains the List< BonusEntity >

BonusEntity will contains the following fields(All fields are String)

Empid BonusDate BonusAmount Dept

I need to sort the ArrayList in Map based on the BonusDate descending order,Can anyone help Thanks in advance.

Please improve your question quality. You can find more tips in: How do I ask a good question? and How to create a Minimal, Complete, and Verifiable example pages. — Szymon Stepniak
– Szymon Stepniak, Commented Jul 28, 2017 at 6:46
Entity class can implement Comparable implement Compare to as @Override public int compareTo(BonusEntity o) { return o.bonusdate.compareTo(this.bonusdate); } and sort list using Collections.sort(list); keep in mind that using string for holding date value will give you some unexpected results, use Date class instead of string — Ganesh Karewad
– Ganesh Karewad, Commented Jul 28, 2017 at 7:00

Loic Mouchard · Accepted Answer · 2017-07-28 06:51:00Z

0

You should create a Comparator that applies to your class BonusEntity and use it via the Collections.sort method.

answered Jul 28, 2017 at 6:51

Loic Mouchard

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2 Comments

Alternatively, have BonusEntity implement Comparable<BonusEntity> then call List.sort()

Also possible, with Comparable you'll define one natural sort for the class. You can define as many Comparator as you can need/imagine.