Dr. Cliff Click&#x27;s Google talk on Lock-Free Hashtable is here: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;HJ-719EGIts" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;HJ-719EGIts</a><p>Acc to Dr. Click, if you do not have 30+ CPUs in a single machine, ConcurrentHashMap (built-in to the JDK)  will do the trick more often than not. The talk is really worth it, if you&#x27;re curious about the design, esp.<p>Dr. Click also had memorable debate with Rich Hickey over STMs. He works at h2o.ai and wrote about building a Key-Value store two years ago: <a href="http:&#x2F;&#x2F;blog.h2o.ai&#x2F;2014&#x2F;02&#x2F;kv-store-memory-analytics&#x2F;" rel="nofollow">http:&#x2F;&#x2F;blog.h2o.ai&#x2F;2014&#x2F;02&#x2F;kv-store-memory-analytics&#x2F;</a>