New Tutorials:   KOTLIN    JAVASCRIPT    SASS/SCSS    PL/SQL  
See the Tutorial List

CopyOnWriteArrayList


In Java, CopyOnWriteArrayList class was introduced in JDK 1.5. This class implements the List interface. It is a modified version of ArrayList. it is very costly because each time when updating is performed a cloned copy is created. It is threaded safe. In this class remove operation can not be performed, if performed UnsupportedOperationException error will occur.

copywritearray-list

Below are the methods of CopyOnWriteArrayListClass


S.no. Method Description
1 add(E e) It is used to add an element to the end of the list.
2 add(int index, E element) It is used to add an element at the specified position of the list.
3 add(int index, Collection c) It is used to add an element at the specified collection at the specified position of the list.
4 clear() It is used to remove all the elements from the list.
5 equals(Object o) It is used to compare an element from another element in the list.
6 get(int index) It is used to get the element from the specified position in the list.
7 hashCode() It is used to get hash code from the list.
8 indexOf(Object o) It is used to get the first element from the list. If the list is empty then it returns -1.
9 Iterator() It returns all the elements from the list. Using Iterator.
10 lastIndexOf(Object o) It is used to get the Last element from the list. If the list is empty then it returns -1.
11 listIterator() It is used to get the Iterated list in a proper sequence.
12 remove(int index) It is used to remove the specified element from the list.
13 removeRange(intfromIndex, inttoIndex) It is used to remove an element from the specified range.
14 set(int index, E element) It is used to replace an element from the specified element.
15 subList(intfromIndex, inttoIndex) It is used to get elements from the specified range.
16 toArray(T[] a) It is used to get all elements of the list in a proper sequence.
17 toString() It is used to get string representation of the list

Example:

	
import java.util.concurrent.CopyOnWriteArrayList; 
import java.util.*; 

class CopyOnWriteArrayListDemo1 extends Thread { 

    static CopyOnWriteArrayListobj = new CopyOnWriteArrayList(); 
    public void run() 
    { 
obj.add("Green"); 
    } 
    public static void main(String[] args) throws InterruptedException
    { 
obj.add("Red"); 
obj.add("Blue"); 
obj.add("Pink"); 
	
        CopyOnWriteArrayListDemo1 obj1 = new CopyOnWriteArrayListDemo1 (); 
obj1.run(); 
Thread.sleep(1000); 
        Iterator a = obj.iterator(); 
        while (a.hasNext()) 
	{ 
            String s = (String)a.next(); 
System.out.println(s); 
Thread.sleep(1000); 
        } 
System.out.println(obj); 
    } 
}
	

copywritearray-list-example