How to Configure Java Priority Queue to Handle Duplicate Elements? Last Updated : 16 Feb, 2024 Comments Improve Suggest changes Like Article Like Report In Java, PriorityQueue is the data structure that stores the elements based on their priorities and provides operations to efficiently retrieve and manipulate these elements based on their priorities. PriorityQueue handles the duplicate elements using a comparator. Comparator is a pre-defined interface, and it is part of the java.util package. It is used to define a custom ordering for objects of a class that do not have a natural ordering. In this article, we will learn how to configure Java Priority Queue to handle duplicate elements. Syntax:Comparator<T> comparator = (o1, o2) -> { //Compare o1 and o2 and return an integer // If o1 ordered before o2, it will return negative integer // If o1 and o2 are considered equal, it returns zero. // If o1 ordered after o2, it will return positive integer };Here, T: It represents the type of objects being comparedLambda expressions can be used to implement the comparison logic between o1 and o2 objects.A comparator can be used to configure a priority queue to handle duplicate elements based on the custom order defined by the comparator.Step-by-Step ImplementationCreate a class named GfgComparator and write the main method inside the class.Define the custom comparator to handle the duplicate elements in the priority queue.Create an instance of the priority queue using the priority queue data structure.Add the elements into the priority list. Queues include the duplicate elements, and comparators handle the duplicate elements.Print the resultant priority queue.Program to Configure Priority Queue to Handle Duplicate Elements in JavaBelow is the Program to Configure Priority Queue to Handle Duplicate Elements: Java // Java program to configure Priority Queue to handle duplicate elements import java.util.Comparator; import java.util.PriorityQueue; public class GfgComparator { public static void main(String args[]) { // define a custom comparator that considers elements equal if they have the same value Comparator<Integer> customComparator = Comparator.comparingInt(i -> i); // create PriorityQueue with the custom comparator PriorityQueue<Integer> priorityQueue = new PriorityQueue<>(customComparator); // add elements to the PriorityQueue priorityQueue.add(5); priorityQueue.add(2); priorityQueue.add(7); priorityQueue.add(2); // duplicate elements priorityQueue.add(5); // duplicate elements // print the PriorityQueue System.out.println(priorityQueue); } } Output[2, 2, 7, 5, 5] Explanation of the Program:We have defined a custom comparator customComparator that compares integers based on their natural ordering.The we have created a PriorityQueue named priorityQueue with this custom comparator.After that we have added several elements to the priority queue, including duplicate elements.At last, it prints the priority queue. Note: The order of elements in the output may vary due to the nature of priority queues. Comment More infoAdvertise with us Next Article How to Configure Java Priority Queue to Handle Duplicate Elements? S seepanarajvskq Follow Improve Article Tags : Java Java Programs priority-queue java-priority-queue Java Examples +1 More Practice Tags : Javapriority-queue Similar Reads How to Handle Null Elements in a PriorityQueue in Java? In Java, a Priority Queue is an abstract data type similar to a regular queue or stack, but with a key difference like elements are dequeued based on their priority. Regarding the null value property, the PriorityQueue class does not allow null elements. Attempting to add a null element will result 3 min read Java Program to Handle Duplicate Elements in a PriorityQueue While Maintaining Order In Java, elements in a Priority Queue are arranged according to their priority, which is based on a priority heap. 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