title: Working of single-threaded partition in Hazelcast for concurrent update request on the same key
body: <p>Referring to answer given on <a href="https://stackoverflow.com/questions/44854870/hazelcast-imap-concurrent-updates-to-the-same-key-different-value">Hazelcast IMap - Concurrent updates to the same key, different value</a> by @tom.bujok </p>
  
  <p>It says "<strong>Each partition is single-threaded, there is only one partition-thread handling each partition. So two update for a single key are handled by a single partition-thread. If both updated keys land in the same partition, these operations will be sequential on a single partition-thread</strong>"</p>
  
  <p>Let's say two update request is send to same key for the IMap, when single partition-thread is executing request 1, What will happen to request 2 for the same key? Does hazelcast puts <strong>request 2 in some queue</strong> or will <strong>single partition-thread locks the partition</strong> while executing request 1?</p>