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HashMap 和 Hashtable 的区别 **线程是否安全：**HashMap 是非线程安全的，Hashtable 是线程安全的,因为 Hashtable 内部的方法基本都经过synchronized 修饰。（如果你要保证线程安全的话就使用 ConcurrentHashMap 吧！）；效率：...

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原题Java面试题: 基础考核-拆箱装箱, 数据类型, MAPhttps://glory.blog.csdn.net/article/details/117279415答案解析问题1参考答案A 运行时异常解题思路和原因(Integer) null 在拆箱过程中有NPE问题我的思考如果需要返回null...

Java面试题: 基础考核-拆箱装箱, 数据类型, MAP

目录1. 以下程序输出内容是？2.以下程序输出内容是？3. 以下程序输出内容是？参考答案1. 以下程序输出内容是？public class Parsing { /** * Returns Integer corresponding to s, or null if s is null. * @thr...

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