* the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot
   * exists, a CAS is tried.  Retries proceed by "double hashing",
   * using a secondary hash (Marsaglia XorShift) to try to find a
   * free slot.
   *
   * The table size is capped because, when there are more threads

          // same freshness, generate again.
          return invokeGeneratorMethod(emptyGenerate);
        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {
        // never generated empty instance for this type before.
        Object emptyInstance = invokeGeneratorMethod(emptyGenerate);

   * the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot
   * exists, a CAS is tried.  Retries proceed by "double hashing",
   * using a secondary hash (Marsaglia XorShift) to try to find a
   * free slot.
   *
   * The table size is capped because, when there are more threads

   * usually have much noticeable impact. A value of one permits only one thread to modify the map
   * at a time, but since read operations can proceed concurrently, this still yields higher
   * concurrency than full synchronization. Defaults to 4.
   *
   * <p><b>Note:</b> Prior to Guava release 9.0, the default was 16. It is possible the default will

              }
            })
        .start();

    // wait for the computingEntry to be created
    computationStarted.await();
    cache.invalidateAll();
    // let the computation proceed
    computingLatch.countDown();
    // don't check cache.size() until we know the get("b") call is complete
    computationComplete.await();

   * the capacity, it is doubled in size unless some other thread
   * holds the lock. If a hashed slot is empty, and lock is
   * available, a new Cell is created. Otherwise, if the slot
   * exists, a CAS is tried.  Retries proceed by "double hashing",
   * using a secondary hash (Marsaglia XorShift) to try to find a
   * free slot.
   *
   * The table size is capped because, when there are more threads

          // same freshness, generate again.
          return invokeGeneratorMethod(emptyGenerate);
        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {
        // never generated empty instance for this type before.
        Object emptyInstance = invokeGeneratorMethod(emptyGenerate);

            // If this CAS succeeds, we know that the provided callable will never be invoked,
            // so when oldFuture completes it is safe to allow the next submitted task to
            // proceed. Doing this immediately here lets the next task run without waiting for
            // the cancelled task's executor to run the noop AsyncCallable.
            //
            // ---
            //

 * read-write locks. Conceptually, lock striping is the technique of dividing a lock into many
 * <i>stripes</i>, increasing the granularity of a single lock and allowing independent operations
 * to lock different stripes and proceed concurrently, instead of creating contention for a single
 * lock.
 *
 * <p>The guarantee provided by this class is that equal keys lead to the same lock (or semaphore),

  `Ugh!' said the Lory, with a shiver.

  `I beg your pardon!' said the Mouse, frowning, but very
politely:  `Did you speak?'

  `Not I!' said the Lory hastily.

  `I thought you did,' said the Mouse.  `--I proceed.  "Edwin and
Morcar, the earls of Mercia and Northumbria, declared for him:
and even Stigand, the patriotic archbishop of Canterbury, found
it advisable--"'

  `Found WHAT?' said the Duck.