Check if arraylist is empty java – Java Program to Check if ArrayList is Empty

Check if arraylist is empty java: In the previous article, we have seen Java Program to Add Elements into an ArrayList

In this article we are going to see how we can check if an ArrayList is empty or not.

Java Program to Check if ArrayList is Empty

Check if arraylist is empty java: In ArrayList there is an isEmpty() method which is used to check if arraylist is empty or not. This method returns true is arraylist is not empty else returns false if arraylist is empty.

Sysntax:

Sample_ArrayList.isEmpty();

Where,

  • Sample_ArrayList represents an ArrayList
  • isEmpty() is the predefined ArrayList method

Let’s see different ways to check if an ArrayList is empty or not.

Method-1: Java Program to Check if ArrayList is Empty By Using isEmpty() Method of ArrayList

Approach:

  • Create an arraylist
  • Check arraylist is empty or not by using inbuilt method isEmpty( )

Program:

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
        // Creating an empty ArrayList
        ArrayList<String> arr = new ArrayList<String>();
        
        //checking arraylist is empty or not 
        //without adding any element to the arraylist
        //so it will print arraylist is empty
        boolean check=arr.isEmpty();
        if (check == true)
            System.out.println("The arraylist is empty");
        else
            System.out.println("The arraylist is not empty");
            
        // Adding elements to the arrayList
        arr.add("One");
        arr.add("Two");
        arr.add("Three");
        // Displaying the list
        System.out.println("ArrayList :"+arr);

        //checking arraylist is empty or not 
        //after adding elements to the arraylist
        //so it will print arraylist is empty
        if(arr.isEmpty())
            System.out.println("The arraylist is empty");
        else
            System.out.println("The arraylist is not empty");
    }
}



Output:

The arraylist is empty
ArrayList :[One, Two, Three]
The arraylist is not empty

Method-2: Java Program to Check if ArrayList is Empty By Using User Defined Method

Approach:

  • Create an arraylist
  • Run the user-defined method printEmptyCheck( ) on the empty arraylist to check if it is empty.
  • Inside user defined method, we will use inbuilt isEmpty( ) function to check if the arrayList is empty or not.

Program:

import java.util.*;
public class Main
{
    public static void main(String[] args)
    {
        // Creating an empty ArrayList
        ArrayList<String> arr = new ArrayList<String>();
        //calling the printEmptyCheck() user defined method before adding any element to arraylist
        printEmptyCheck(arr);
        // Adding elements to the arrayList
        arr.add("One");
        arr.add("Two");
        arr.add("Three");
        // Displaying the list
        System.out.println("ArrayList :"+arr);
        //calling the printEmptyCheck() user defined method
        printEmptyCheck(arr);
    }
    
    //user defined method to check if arraylist is empty or not
    //by using predefined method isEmpty() of ArrayList 
    //we will check arraylist is empty or not
    static void printEmptyCheck(ArrayList arr)
    {
        if(arr.isEmpty())
            System.out.println("The arraylist is empty");
        else
            System.out.println("The arraylist is not empty");
    }
}



Output:

The arraylist is empty
ArrayList :[One, Two, Three]
The arraylist is not empty

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