84669 person learning
152542 person learning
20005 person learning
5487 person learning
7821 person learning
359900 person learning
3350 person learning
180660 person learning
48569 person learning
18603 person learning
40936 person learning
1549 person learning
1183 person learning
32909 person learning
今天看到Arrays.asList()方法中使用的是一个私有的ArrayList使用了参数为数组的构造器,为什么ArrayList本身不带有这样的构造器呢?
拥有18年软件开发和IT教学经验。曾任多家上市公司技术总监、架构师、项目经理、高级软件工程师等职务。 网络人气名人讲师,...
看源码:
/** * The array buffer into which the elements of the ArrayList are stored. * The capacity of the ArrayList is the length of this array buffer. Any * empty ArrayList with elementData == EMPTY_ELEMENTDATA will be expanded to * DEFAULT_CAPACITY when the first element is added. */ private transient Object[] elementData;
/** * Constructs a list containing the elements of the specified * collection, in the order they are returned by the collection's * iterator. * * @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; // c.toArray might (incorrectly) not return Object[] (see 6260652) if (elementData.getClass() != Object[].class) elementData = Arrays.copyOf(elementData, size, Object[].class); }
看源码: