Thursday, July 2, 2026
HomeLanguagesJavaCopyOnWriteArrayList addIfAbsent() method in Java

CopyOnWriteArrayList addIfAbsent() method in Java

The addIfAbsent(E e) method of CopyOnWriteArrayList appends the element passed in the parameter to the end of the List if the element is not present in the list. The function returns true on addition of new element to the list.

Syntax:

public boolean addIfAbsent(E e)

Parameters: The function accepts a single mandatory parameter element which specifies the element to be appended to the list if it is not present.

Return Value: The function returns true if it is added to the list.

Below programs illustrate the above function:

Program 1:




// Java Program to illustrate the CopyOnWriteArrayList
// addIfAbsent(element) method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<Integer> ArrLis
            = new CopyOnWriteArrayList<Integer>();
  
        // Add elements
        ArrLis.addIfAbsent(2);
        ArrLis.addIfAbsent(3);
        ArrLis.addIfAbsent(4);
        ArrLis.addIfAbsent(7);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: " 
                                           + ArrLis);
  
        System.out.println("On adding 4 it returns " 
          + ArrLis.addIfAbsent(4) + " as it is present");
    }
}


Output:

CopyOnWriteArrayList: [2, 3, 4, 7]
On adding 4 it returns false as it is present

Program 2:




// Java Program to illustrate the CopyOnWriteArrayList
// addIfAbsent(element) method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<String> ArrLis
            = new CopyOnWriteArrayList<String>();
  
        // Add elements
        ArrLis.addIfAbsent("gopal");
        ArrLis.addIfAbsent("gfg");
        ArrLis.addIfAbsent("jgec");
        ArrLis.addIfAbsent("sudo");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: " + ArrLis);
  
        System.out.println("On adding 'sudo' it returns " 
            + ArrLis.addIfAbsent("sudo") + " as it is present");
    }
}


Output:

CopyOnWriteArrayList: [gopal, gfg, jgec, sudo]
On adding 'sudo' it returns false as it is present

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#addIfAbsent-E-

Dominic
Dominichttp://wardslaus.com
infosec,malicious & dos attacks generator, boot rom exploit philanthropist , wild hacker , game developer,
RELATED ARTICLES

5 COMMENTS

Most Popular

Dominic
32519 POSTS0 COMMENTS
Milvus
131 POSTS0 COMMENTS
Nango Kala
6900 POSTS0 COMMENTS
Nicole Veronica
12014 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12110 POSTS0 COMMENTS
Shaida Kate Naidoo
7019 POSTS0 COMMENTS
Ted Musemwa
7262 POSTS0 COMMENTS
Thapelo Manthata
6976 POSTS0 COMMENTS
Umr Jansen
6966 POSTS0 COMMENTS