java Java 中的 CopyOnWriteArrayList get()方法

Java 中的 CopyOnWriteArrayList get()方法

原文:https://www . geeksforgeeks . org/copy onwriterarraylist-get-method-in-Java/

的 get(index) 方法返回指定索引处的元素。

语法:

public E get(int index)

参数:该函数接受一个强制参数索引，该索引指定要返回的元素的索引。

返回值:函数返回给定索引处的元素。

异常:如果指数超出范围，函数将抛出指数。

以下程序说明了上述功能:

程序 1:

// Java Program to illustrate the 
// CopyOnWriteArrayList get() 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);

        // 2nd index in the arraylist
        System.out.println("Element at 2nd index: " 
                                    + ArrLis.get(2));
    }
}

输出:

CopyOnWriteArrayList: [32, 67, 98, 100]
Element at 2nd index: 98

节目 2:

// Java Program to illustrate the 
// CopyOnWriteArrayList get() 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);

        // 4th index element of the arraylist
        // out of range, hence error
        System.out.println("CopyOnWriteArrayList: "
                                    + ArrLis.get(4));
    }
}

输出:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
    at java.util.concurrent.CopyOnWriteArrayList.get(CopyOnWriteArrayList.java:388)
    at java.util.concurrent.CopyOnWriteArrayList.get(CopyOnWriteArrayList.java:397)
    at GFG.main(GFG.java:24)