/** * Constructs a list containing the elements of the specified * collection, in the order they are returned by the collection's * iterator. * 使用集合类对象初始化ArrayList * * @param c the collection whose elements are to be placed into this list * @throws NullPointerException if the specified collection is null */ public ArrayList(Collection<? extends E> c) { elementData = c.toArray(); size = elementData.length; //刚才看了一眼这个toArray方法,确实有时候返回的不是Obdect[], // c.toArray might (incorrectly) not return Object[] (see 6260652) if (elementData.getClass() != Object[].class) elementData = Arrays.copyOf(elementData, size, Object[].class); }
以上为ArrayList的一个构造函数,在里面有一句
c.toArray might (incorrectly) not return Object[] (see 6260652)
这个注释,参见bug6260652,java的bug官网http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6260652
问题就在这儿了,List<String> strList= Arrays.asList("abc");返回的结果是String[],不谢。。。
以下为测试代码
1 public static void main(String[] args) { 2 List<String> stringList= Arrays.asList("test"); 3 Object[] strList=stringList.toArray(); 4 System.out.println(strList.getClass()); 5 }
结果如下: