Java中LinkedList遍歷速度可比ArrayList快!

import java.util.LinkedList;
import java.util.ArrayList;
import java.util.Random;

 public class TestList {
     private static Random random = new Random();
     public static void main(String[] args){
         ArrayList<String> arraylist = new ArrayList<String>();
         LinkedList<String> linkedlist = new LinkedList<String>();
         for(int i=0;i<50000;i++){
             String r = randomString();
             arraylist.add(r);
             linkedlist.add(r);
         }

         System.out.println("arraylist size "+arraylist.size());
         System.out.println("linkedlist size "+linkedlist.size());
         System.out.println("------");
         long begin = System.currentTimeMillis();
         for(int i=0;i<1000;i++){
             for(int j=0;j<arraylist.size();j++){
            	 String s=arraylist.get(j);
             }
         }
         System.out.println("arraylist get(n) time "+(System.currentTimeMillis()-begin));

         begin = System.currentTimeMillis();
         for(int i=0;i<1000;i++){
             for(String s:arraylist){
             }
         }
         System.out.println("arraylist foreach time "+(System.currentTimeMillis()-begin));

         begin = System.currentTimeMillis();
         for(int i=0;i<1;i++)
         for(int j=0;j<linkedlist.size();j++){
        	 String s=linkedlist.get(j);
         }
         System.out.println("linkedlist get(n) time "+(System.currentTimeMillis()-begin)*1000);

         begin = System.currentTimeMillis();
         for(int i=0;i<1000;i++)
         for(String s:linkedlist){
//             linkedlist.get(j);
         }
         System.out.println("linkedlist foreach time "+(System.currentTimeMillis()-begin));


     }
     protected static String randomString() {
         return Long.toString(random.nextLong(), 36);
     }
 }

arraylist size 50000
linkedlist size 50000
------
arraylist get(n) time 562
arraylist foreach time 1703
linkedlist get(n) time 1922000
linkedlist foreach time 813

結論linkedlist foreach比arraylist foreach快