コレクションクラスの操作について

package com.zcl.collection;

import java.util.ArrayList;
import java.util.Collection;

public class CollectionToArray
{
    /**
     * Collection ：
     */

    public static void main(String[] args) {
        Collection collection1=new ArrayList();
        collection1.add("000");
        collection1.add("111");
        collection1.add("222");
        System.out.println(" collection1 :"+collection1.size());
        System.out.println(" collection1 ："+collection1);
        collection1.remove("000");
        System.out.println(" collection1 000 ："+collection1);
        System.out.println(" collection1 000："+collection1.contains("000"));
        System.out.println(" collection1 111："+collection1.contains("111"));
        Collection collection2=new ArrayList();
        collection2.addAll(collection1);
        System.out.println(" collection2 ："+collection2);
        collection2.clear();
        System.out.println(" collection2 ："+collection2.isEmpty());
        Object s[]=collection1.toArray();
        for(int i=0;i<s.length;i++)
        {
            System.out.println(s[i]);
        }
        
    }

}