Java ArrayList操作

import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;

public class Study {
    public static void main(String[] args) throws Exception {
        List<String> list = new ArrayList<String>();
        list.add("abcd");
        list.add("1234");
        
        Iterator<String> it = list.iterator();
        while( it.hasNext() ){
            System.out.println( it.next() );
        }
        
        for( int i=0; i<list.size(); i++ ){
            System.out.println( list.get(i) );
        }
    }
}