Java ConcurrentHashMap keySet() Method

The keySet() method of ConcurrentHashMap class returns a Set view of the keys contained in this map. The set is stacked by the map, so changes to the map are reflected in the set, and vice-versa.

Syntax

public ConcurrentHashMap.KeySetView<K,V> keySet()

public ConcurrentHashMap.KeySetView<K,V> keySet(V mappedValue)

Parameter

No parameter is passed.

Returns

the set view

Throws

No Exception is thrown.

Example 1

import java.util.*; 
import java.util.concurrent.*; 
  
public class ConcurrentHashMapKeySetExample1 { 
    public static void main(String[] args) 
    { 
        ConcurrentHashMap<Integer, String>  conmap = new ConcurrentHashMap<Integer, String>(); 
        conmap.put(10, "Java"); 
        conmap.put(11, ".net"); 
        conmap.put(20, "php"); 
        conmap.put(12, "C"); 
        conmap.put(30, "C++"); 
     // print statement.
        System.out.println(" Map : " + conmap); 
         System.out.println("keySet : " + conmap.keySet());
    } 
} 

Test it Now

Output:

Map : {20=php, 10=Java, 11=.net, 12=C, 30=C++}
keySet : [20, 10, 11, 12, 30]

Example 2

import java.util.*; 
import java.util.concurrent.*; 
  
public class ConcurrentHashMapKeySetExample2 { 
    public static void main(String[] args) 
    { 
        ConcurrentHashMap<String , String>  conmap = new ConcurrentHashMap<String, String>(); 
        conmap.put("A", "Java"); 
        conmap.put("B", ".net"); 
        conmap.put("C", "php"); 
        conmap.put("D", "C"); 
        conmap.put("E", "C++"); 
        // print statement
        System.out.println(" Using KeySet method : " + conmap.keySet("php")); 
        Enumeration enumr = conmap.keys(); 
        System.out.println(" enumeration of keys are:"); 
        while (enumr.hasMoreElements()) { 
            System.out.println(enumr.nextElement()); 
        } 
    } 
}

Test it Now

Output:

Using KeySet : [A, B, C, D, E]
 enumeration of keys are:
A
B
C
D
E

Next TopicJava ConcurrentHashMap

← prev next →

For Videos Join Our Youtube Channel: Join Now

Feedback

Send your Feedback to [email protected]

Help Others, Please Share

Learn Latest Tutorials

Splunk

SPSS

Swagger

Transact-SQL

Tumblr

ReactJS

Regex

Reinforcement Learning

R Programming

RxJS

React Native

Python Design Patterns

Python Pillow

Python Turtle

Keras

Preparation

Aptitude

Reasoning

Verbal Ability

Interview Questions

Company Questions

Trending Technologies

Artificial Intelligence

AWS

Selenium

Cloud Computing

Hadoop

ReactJS

Data Science

Angular 7

Blockchain

Git

Machine Learning

DevOps

B.Tech / MCA

DBMS

Data Structures

DAA

Operating System

Computer Network

Compiler Design

Computer Organization

Discrete Mathematics

Ethical Hacking

Computer Graphics

Software Engineering

Web Technology

Cyber Security

Automata

C Programming

C++

Java

.Net

Python

Programs

Control System

Data Mining

Data Warehouse

^{Like/Subscribe us for latest updates or newsletter}