Java Collection isEmpty() Method

The isEmpty() method of Java Collection Interface returns the boolean value 'true' if this collection contains no elements.

Syntax

Parameters

Return

The isEmpty () method returns the boolean value 'true' if this collection contains no elements else it returns false.

Example 1

import java.util.Collection;
import java.util.concurrent.ConcurrentLinkedQueue;
public class JavaCollectionIsEmptyExample1 {
    public static void main(String[] args) {
        Collection<Integer> collection = new ConcurrentLinkedQueue<Integer>();
        //returns true if the queue is empty
        if(collection.isEmpty()){
            System.out.println("The queue is empty.");
        }
        else{
            System.out.println("Elements are : "+collection);
        }
    }
}

Test it Now

Output:

The queue is empty.

Example 2

import java.util.Collection;
import java.util.concurrent.ConcurrentLinkedQueue;
public class JavaCollectionIsEmptyExample2 {
    public static void main(String[] args) {
        Collection<Integer> collection = new ConcurrentLinkedQueue<Integer>();
        //returns an exception for null element
        collection.add(null);
        //returns true if the queue is empty
        if(collection.isEmpty()){
            System.out.println("Add some elements because the queue is empty.");
        }
        else{
            System.out.println("Elements are : "+collection);
        }
    }
}

Test it Now

Output:

Exception in thread "main" java.lang.NullPointerException
	at java.util.concurrent.ConcurrentLinkedQueue.checkNotNull(ConcurrentLinkedQueue.java:920)
	at java.util.concurrent.ConcurrentLinkedQueue.offer(ConcurrentLinkedQueue.java:327)
	at java.util.concurrent.ConcurrentLinkedQueue.add(ConcurrentLinkedQueue.java:297)
	at com.javaTpoint.JavaCollectionIsEmptyExample2.main(JavaCollectionIsEmptyExample2.java:9)

Example 3

import java.util.Collection;
import java.util.concurrent.ConcurrentLinkedQueue;
public class JavaCollectionIsEmptyExample3 {
    public static void main(String[] args) {
        Collection<Integer> collection = new ConcurrentLinkedQueue<Integer>();
        for (int i = 1; i <= 5; i++){
            collection.add(i);
        }
        if(collection.isEmpty()){
            System.out.println("isEmpty() method returns "+collection.isEmpty());
            System.out.println("Add some elements because the queue is empty.");
        }
        else{
            System.out.println("isEmpty() method returns "+collection.isEmpty());
            System.out.println("Elements are : "+collection);
        }
    }
}

Test it Now

Output:

isEmpty() method returns false
Elements are : [1, 2, 3, 4, 5]

Next TopicJava Collection

← 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}