摘要：
Like other members, a nested class can be declared static (or not). A static nested class is called just that: a static nested class. A nonstatic nested class is called an inner class. － Nested clas... 阅读全文
摘要：
两个类都是实现了Map接口Hashtable是线程安全的，HashMap不是，所以HashMap更高效Hashtable不容许null作为键值，而HashMap 容许哦，呵呵HashMap去掉了contains()方法。 阅读全文