title: Is ConcurrentHashMap totally safe?
body: <p>this is a passage from JavaDoc regarding <code>ConcurrentHashMap</code>. It says retrieval operations generally do not block, so may overlap with update operations. Does this mean the <code>get()</code> method is not thread safe?</p>
  
  <blockquote>
    <p>"However, even though all operations are thread-safe, retrieval
    operations do not entail locking, and there is not any support for
    locking the entire table in a way that prevents all access. This class
    is fully interoperable with Hashtable in programs that rely on its
    thread safety but not on its synchronization details.</p>
    
    <p>Retrieval operations (including get) generally do not block, so may
    overlap with update operations (including put and remove). Retrievals
    reflect the results of the most recently completed update operations
    holding upon their onset."</p>
  </blockquote>