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Showing posts with the label Comparator

How to sort collections in Java 8?

Introduction In this post, we will explore different ways to sort Java collections in a certain order. Java platform provides a  Collections framework that represents a group of objects. All the Java classes those implement the Collection interface have by default implemented the sort method i.e. Collections.sort(list/set/Array) Java classes like String, Date, Integer, Double, Float, Long, Integer etc implements the Comparable interface by default. Java provides us with the following two interfaces to compare and sort the custom objects Comparable Interface  public interface Comparable<T> { public int compareTo(T o); } Java 8 also provides the built in Comparator.comparing method that returns an instance of Comparable. Comparator Interface public interface Comparator<T> { int compare(T o1, T o2); } In this post we will use the following student class for practice. public class Student{ public String name; public Integer age; public St