1Java线程的6种状态及切换
https://blog.csdn.net/pange1991/article/details/53860651/
2进程和线程的区别
https://www.cnblogs.com/lgk8023/p/6430592.html
3进程间如何通讯
https://blog.csdn.net/wh_sjc/article/details/70283843
4线程间如何通讯
https://blog.csdn.net/ls5718/article/details/51878770
5HashMap的数据结构是什么?如何实现的
https://www.cnblogs.com/dassmeta/p/5338955.html
6HashMap和HashTable有什么不同
http://www.cnblogs.com/xinzhao/p/5644175.html
7HashMap和ConcurrentHashMap有什么不同
https://javadoop.com/post/hashmap