hashtable vs hashmap

看面经看到别人问hashtable和hashmap的区别 这里是网上查到的

• Hashtable is synchronized, whereas HashMap is not. This makes HashMap better for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones.
• Hashtable does not allow null keys or values. HashMap allows one null key and any number of null values.
• One of HashMap's subclasses is LinkedHashMap, so in the event that you'd want predictable iteration order (which is insertion order by default), you could easily swap out the HashMap for a LinkedHashMap. This wouldn't be as easy if you were using Hashtable.
  

但是我表示我看不懂 我们一般用的是table还是map 比如面试说的那种找words frequence  然后用hash  这个时候我们用的是table还是map？


能不能有哪位高手举个例子讲解一下 真的有点迷糊

hashtable 是线程安全的，如果你需要多线程的修改一个map 需要用 hashtable， 但是如果不需要的话 hashmap还是性能好点 毕竟不需要同步，  linkedHashMap 是说你可以 按照你 put 进去的 elements的顺序 读 这些 elements。