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The contains(E e) method of CopyOnWriteArraySet checks if a given element is present in the Set or not. 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 Set. Return Value: The function returns true if the element is present else it returns false. Below programs illustrate the above function: Program 1:

Java

// Java Program to illustrate the CopyOnWriteArraySet
// contains() method in Java

import java.util.concurrent.CopyOnWriteArraySet;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<Integer> ArrSet
            = new CopyOnWriteArraySet<Integer>();

        // Add elements
        ArrSet.add(32);
        ArrSet.add(67);
        ArrSet.add(67);
        ArrSet.add(100);

        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);

        // check if 100 is present
        // using contains() function
        if (ArrSet.contains(100))
            System.out.println("100 is "
                               + "present in the Set");
        else
            System.out.println("100 is "
                               + "not present in the Set");

        // check if 20 is present
        // using contains() function
        if (ArrSet.contains(20))
            System.out.println("20 is "
                               + "present in the Set");
        else
            System.out.println("20 is "
                               + "not present in the Set");
    }
}

Output:

CopyOnWriteArraySet: [32, 67, 100]
100 is present in the Set
20 is not present in the Set

Program 2:

Java

// Java Program to illustrate the CopyOnWriteArraySet
// contains() method in Java

import java.util.concurrent.CopyOnWriteArraySet;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<String> ArrSet
            = new CopyOnWriteArraySet<String>();

        // Add elements
        ArrSet.add("geeks");
        ArrSet.add("gfg");
        ArrSet.add("jgec");
        ArrSet.add("sudo");

        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);

        // check using contains() function
        if (ArrSet.contains("gfg"))
            System.out.println("gfg is "
                               + "present in the Set");
        else
            System.out.println("gfg is "
                               + "not present in the Set");

        // check using contains() function
        if (ArrSet.contains("best"))
            System.out.println("best is "
                               + "present in the Set");
        else
            System.out.println("best is "
                               + "not present in the Set");
    }
}

Output:

CopyOnWriteArraySet: [geeks, gfg, jgec, sudo]
gfg is present in the Set
best is not present in the Set

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArraySet.html#contains-java.lang.Object-

CopyOnWriteArraySet contains() method in Java

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