Java中CopyOnWriteArraySet中的isEmpty()方法

isEmpty(E e) 方法检查集合是否为空。当集合为空时返回true，否则返回false。

语法:

public boolean isEmpty()

返回值: 当集合为空时返回 true ，否则返回 false 。

下面的程序说明了上面的函数:

程序1:

// Java Program to illustrate the
// isEmpty() method in CopyOnWriteArraySet
 
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(98);
        ArrSet.add(100);
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: " + ArrSet);
 
        // check using function
        if (ArrSet.isEmpty())
            System.out.println("\nSet is empty");
        else
            System.out.println("\nSet is not empty");
    }
}

输出:

CopyOnWriteArraySet: [32, 67, 98, 100]

Set is not empty

程序2:

// Java Program to illustrate the
// isEmpty() method in CopyOnWriteArraySet
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>();
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);
 
        // check using function
        if (ArrSet.isEmpty())
            System.out.println("\nSet is empty");
        else
            System.out.println("\nSet is not empty");
    }
}

输出: