关于集合类的操作

package com.zcl.collection;import java.util.ArrayList;import java.util.Collection;public class CollectionToArray{    /**     * Collection方法的测试：     */    public static void main(String[] args) {        Collection collection1=new ArrayList();        collection1.add("000");        collection1.add("111");        collection1.add("222");        System.out.println("集合collection1的大小:"+collection1.size());        System.out.println("集合collection1的内容："+collection1);        collection1.remove("000");        System.out.println("集合collection1移除000后的内容："+collection1);        System.out.println("集合collection1是否包含000："+collection1.contains("000"));        System.out.println("集合collection1是否包含111："+collection1.contains("111"));        Collection collection2=new ArrayList();        collection2.addAll(collection1);        System.out.println("集合collection2的内容："+collection2);        collection2.clear();        System.out.println("集合collection2是否为空："+collection2.isEmpty());        Object s[]=collection1.toArray();        for(int i=0;i<s.length;i++)        {            System.out.println(s[i]);        }            }}