泛型举例。作为容器的的另一个例子。假如我们需要构建一个可以应用于各种类型的对象工具，就需要用到泛型。举例：RandomList

public class RandomList
     
       {    private ArrayList
      
        storage = new ArrayList
       
        ();    private Random rand = new Random(47);    public void add(T item) {//新增对象        storage.add(item);    }    public T select() {//获取对象        return storage.get(rand.nextInt(storage.size()));    }    public static void main(String[] args) {//测试        RandomList
        
          rs = new RandomList
         
          ();        for (String s : ("The quick brown fox jumped over "                + "the lazy brown dog").split(" "))            rs.add(s);        for (int i = 0; i < 11; i++)            System.out.print(rs.select() + " ");    }}