What are the differences between a
HashMap and a
Hashtable in Java?
Which is more efficient for non-threaded applications?
There are several differences between HashMap and Hashtable in Java:
- Hashtable is synchronized, whereas HashMap is not. This makes
HashMapbetter for non-threaded applications, as unsynchronized Objects typically perform better than synchronized ones.
Hashtabledoes not allow null keys or values.
HashMapallows one null key and any number of
- 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
LinkedHashMap. This wouldn’t be as easy if you were using
Since synchronization is not an issue for you, I’d recommend
HashMap. If synchronization becomes an issue, you may also look at ConcurrentHashMap.