interface Iterator{
boolean hasNext();
Object next();
void remove();
}
Iterator it = new ArrayList().iterator();
public class ArrayList extends AbstractList implements List{
//Collection中定义了方法iterator() 实现类ArrayList必须重写这个方法
public Iterator iterator(){
return new Itr();
}
//定义了一个内部类,实现了Iterator接口
private class Itr implements Iterator{
public boolean hasNext(){ return false;}
public Object next(){return null;}
public void remove(){}
}
}