The contains(E e) method of CopyOnWriteArrayList checks if a given element is present in the list or not. If the element atleast occurs one time, then the function returns true, else it returns false.
Syntax:
public boolean contains(Object o)
Parameters: The function accepts a single mandatory parametero which specifies the element whose appearance is to be checked in the list.
Return Value: The function returns true if the element is present atleast one time in the list, else it returns false.
Below programs illustrate the above function:
Program 1:
// Java Program to illustrate the CopyOnWriteArrayList// contains() method in Javaimport 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(32);        ArrLis.add(67);        ArrLis.add(98);        ArrLis.add(100);          // print CopyOnWriteArrayList        System.out.println("CopyOnWriteArrayList: " + ArrLis);          // check using function        if (ArrLis.contains(100))            System.out.println("100 is present in the list");        else            System.out.println("100 is not present in the list");          // check using function        if (ArrLis.contains(20))            System.out.println("20 is present in the list");        else            System.out.println("20 is not present in the list");    }} |
Output:
CopyOnWriteArrayList: [32, 67, 98, 100] 100 is present in the list 20 is not present in the list
Program 2:
// Java Program to illustrate the CopyOnWriteArrayList// contains() method in Javaimport 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.add("gopal");        ArrLis.add("gfg");        ArrLis.add("jgec");        ArrLis.add("sudo");          // print CopyOnWriteArrayList        System.out.println("CopyOnWriteArrayList: " + ArrLis);          // check using function        if (ArrLis.contains("gfg"))            System.out.println("'gfg' is present in the list");        else            System.out.println("'gfg' is not present in the list");          // check using function        if (ArrLis.contains("best"))            System.out.println("'best' is present in the list");        else            System.out.println("'best' is not present in the list");    }} |
Output:
CopyOnWriteArrayList: [gopal, gfg, jgec, sudo] 'gfg' is present in the list 'best' is not present in the list
Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#contains-E-
