Java CopyOnWriteArrayList size()方法

CopyOnWriteArrayList 的 size() 方法返回列表的大小。它返回列表中元素的数量。

语法

public int size()

参数： 该函数不接受任何参数。

返回值： 该函数返回列表的大小。

以下程序说明了上述函数。

程序1 :

// Java Program to illustrate the CopyOnWriteArrayList
// size() 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(32);
        ArrLis.add(67);
        ArrLis.add(98);
        ArrLis.add(100);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: "
                                          + ArrLis);
  
        // size value print
        System.out.println("size of ArrLis: " 
                              + ArrLis.size());
    }
}

输出。

CopyOnWriteArrayList: [32, 67, 98, 100]
size of ArrLis: 4

程序2

// Java Program to illustrate the CopyOnWriteArrayList
// size() 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<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);
  
        // size value print
        System.out.println("size of ArrLis: " 
                                + ArrLis.size());
    }
}

输出。

CopyOnWriteArrayList: [gopal, gfg, jgec, sudo]
size of ArrLis: 4

参考资料: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#size-