CopyOnWriteArrayList add() method in Java Last Updated : 26 Nov, 2018 Summarize Comments Improve Suggest changes Share Like Article Like Report The add(E e) method of CopyOnWriteArrayList inserts the element passed in the parameter to the end of the List or at a specified index in the list. The function returns true on addition of new element to the list. Syntax: public boolean add(E e) or public void add(int index, E element) Parameters: The function accepts two types of parameters which are described below: index: specifies the index at which the element is to be added. The parameter is not mandatory. If this parameter is not passed, then the addition is done at the end of the list. element: specifies the element to be added in the list Return Value: The function returns true on addition in the list. Below programs illustrate the above function: Program 1: Java // Java Program to illustrate the CopyOnWriteArrayList // add(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.add(2); ArrLis.add(3); ArrLis.add(4); ArrLis.add(7); // print CopyOnWriteArrayList System.out.println("CopyOnWriteArrayList: " + ArrLis); System.out.println("On adding 45 it returns " + ArrLis.add(45)); } } Output: CopyOnWriteArrayList: [2, 3, 4, 7] On adding 45 it returns true Program 2: Java // Java Program to illustrate the CopyOnWriteArrayList // add(index, 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 at 0th index ArrLis.add(0, 2); System.out.println("CopyOnWriteArrayList: " + ArrLis); // Add elements at 0th index ArrLis.add(0, 3); System.out.println("CopyOnWriteArrayList: " + ArrLis); // Add elements at 1st index ArrLis.add(1, 4); System.out.println("CopyOnWriteArrayList: " + ArrLis); // Add elements at 2nd index ArrLis.add(2, 7); System.out.println("CopyOnWriteArrayList: " + ArrLis); } } Output: CopyOnWriteArrayList: [2] CopyOnWriteArrayList: [3, 2] CopyOnWriteArrayList: [3, 4, 2] CopyOnWriteArrayList: [3, 4, 7, 2] Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#add-E- Comment More infoAdvertise with us Next Article CopyOnWriteArrayList add() method in Java G gopaldave Follow Improve Article Tags : Misc Java Java-Collections Java - util package Java-Functions Java-CopyOnWriteArrayList +2 More Practice Tags : JavaJava-CollectionsMisc Similar Reads CopyOnWriteArraySet add() method in Java The add(E e) method of CopyOnWriteArraySet inserts the element passed in the parameter to the end of the Set or at a specified index in the Set. The function returns true on addition of new element to the Set. Syntax: public boolean add(E e) Parameters: The function accepts a single mandatory parame 2 min read CopyOnWriteArrayList clear() method in Java The clear() method of CopyOnWriteArrayList erases all the elements in the list. The size of the list becomes zero after the function is called. Syntax: public void clear() Parameters: The function does not accept any parameters. Return Value: The function does not returns anything. Below programs il 1 min read 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 2 min read CopyOnWriteArrayList clone() method in Java The clone() method of CopyOnWriteArrayList returns a shallow copy of the list. The shallow copy contains exactly the same elements at the same index. Syntax: public Object clone() Parameters: The function does not accept any parameters. Return Value: The function returns a clone of the list. Below p 2 min read CopyOnWriteArrayList get() method in Java The get(index) method of CopyOnWriteArrayList returns the element at the specified index. Syntax: public E get(int index) Parameters: The function accepts a mandatory parameter index which specifies the index of the element to be returned. Return Value: The function returns the element at the given 2 min read Like