Java ArrayList remove方法

package com.codingdict;

import java.util.ArrayList;

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

      // create an empty array list with an initial capacity
      ArrayList<Integer> arrlist = new ArrayList<Integer>(5);

      // use add() method to add elements in the deque
      arrlist.add(20);
      arrlist.add(15);
      arrlist.add(30);
      arrlist.add(45);

      System.out.println("Size of list: " + arrlist.size());

      // let us print all the elements available in list
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }  

      // Removes element at 3rd position
      arrlist.remove(2);

      System.out.println("Now, Size of list: " + arrlist.size());

      // let us print all the elements available in list
      for (Integer number : arrlist) {
         System.out.println("Number = " + number);
      }
   }
}