Check whether a list is empty in Java

This post will discuss different ways to check whether a list is empty in Java. A list is empty if and only if it contains no elements.

1. Using `List.isEmpty()` method

The recommended approach is to use the List.isEmpty() method to check for an empty list in Java. Following is a simple example demonstrating usage of this method:

import java.util.ArrayList;

import java.util.List;

class Main {

public static void main(String[] args) {

List<String> list = new ArrayList<>();

if (list == null) {

System.out.println("List is null");

}

if (list.isEmpty()) {

System.out.println("List is empty");

}

else {

System.out.println("List is not empty or null");

}

Instead of explicitly checking if the list is null or empty, you can combine the isEmpty() method with a null check in a single expression, as shown below:

import java.util.Arrays;

import java.util.List;

class Main {

public static void main(String[] args) {

List<Integer> list = Arrays.asList(1, 2, 3);

if (list == null || list.isEmpty()) {

System.out.println("List is empty or null");

}

Or, even better:

import java.util.Arrays;

import java.util.List;

class Main {

public static void main(String[] args) {

List<Integer> list = Arrays.asList(1, 2, 3);

if (list != null && !list.isEmpty()) {

System.out.println("List is not empty");

}

2. Using `List.size()` method

Finally, you can use the List.size() method, which returns the total number of items in it.

import java.util.Arrays;

import java.util.List;

class Main {

public static void main(String[] args) {

List<Integer> list = Arrays.asList(1, 2, 3);

if (list != null && list.size() > 0) {

System.out.println("List is not empty");

} else {

System.out.println("List is empty or null");

}

That’s all about checking whether a list is empty in Java.

Check whether a list is empty in Java

1. Using List.isEmpty() method

2. Using List.size() method

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1. Using `List.isEmpty()` method

2. Using `List.size()` method