ConcurrentHashMap entrySet() method in Java with Examples Last Updated : 30 Oct, 2018 Comments Improve Suggest changes Like Article Like Report The entrySet() method of ConcurrentHashMap in Java is used to create a set from the same elements contained in the concurrent hash map. It basically returns a set view of the concurrent hash map or we can create a new set and store the map elements into them. Syntax: ConcurrentHashMap.entrySet() Parameters: The method does not take any parameter. Return Value: The method returns a set having same elements as the concurrent hash map. Below programs are used to illustrate the working of entrySet() Method: Program 1: Mapping String Values to Integer Keys. Java // Java code to illustrate the entrySet() method import java.util.*; import java.util.concurrent.*; public class ConcurrentHashMapDemo { public static void main(String[] args) { // Creating an empty ConcurrentHashMap ConcurrentHashMap<Integer, String> hash_map = new ConcurrentHashMap<Integer, String>(); // Mapping string values to int keys hash_map.put(10, "Geeks"); hash_map.put(15, "4"); hash_map.put(20, "Geeks"); hash_map.put(25, "Welcomes"); hash_map.put(30, "You"); // Displaying the HashMap System.out.println("Initial Mappings are: " + hash_map); // Using entrySet() to get the set view System.out.println("The set is: " + hash_map.entrySet()); } } Output: Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4} The set is: [20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4] Program 2: Mapping Integer Values to String Keys. Java // Java code to illustrate the entrySet() method import java.util.*; import java.util.concurrent.*; public class ConcurrentHashMapDemo { public static void main(String[] args) { // Creating an empty ConcurrentHashMap ConcurrentHashMap<String, Integer> hash_map = new ConcurrentHashMap<String, Integer>(); // Mapping int values to string keys hash_map.put("Geeks", 10); hash_map.put("4", 15); hash_map.put("Geeks", 20); hash_map.put("Welcomes", 25); hash_map.put("You", 30); // Displaying the HashMap System.out.println("Initial Mappings are: " + hash_map); // Using entrySet() to get the set viewa System.out.println("The set is: " + hash_map.entrySet()); } } Output: Initial Mappings are: {4=15, Geeks=20, You=30, Welcomes=25} The set is: [4=15, Geeks=20, You=30, Welcomes=25] Note: The same operation can be performed with any type of Mappings with variation and combination of different data types. Comment More infoAdvertise with us Next Article ConcurrentHashMap get() Method in Java C chinmoy lenka Follow Improve Article Tags : Misc Java Java-Functions Java-ConcurrentHashMap Practice Tags : JavaMisc Similar Reads ConcurrentHashMap in Java In Java, the ConcurrentHashMap is a thread-safe implementation of the Map interface. It allows multiple threads to read and write data simultaneously, without the need for locking the entire map. Unlike a regular HashMap, which is not thread-safe, ConcurrentHashMap ensures that the operations are th 15+ min read Java ConcurrentHashMap | clear() The clear() method in Java's ConcurrentHashMap class is used to remove all the key-value pairs from the map. 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