}
          };

      @Override
      public void validateClass(Class<? extends Exception> exceptionClass) {
        isValidClass.get(exceptionClass); // throws if invalid; returns safely (and caches) if valid
      }
    }

    enum WeakSetValidator implements GetCheckedTypeValidator {
      INSTANCE;

      /*

        throw new IllegalArgumentException(
            "missing event subscriber for an annotated method. Is " + listener + " registered?");
      }

      // don't try to remove the set if it's empty; that can't be done safely without a lock
      // anyway, if the set is empty it'll just be wrapping an array of length 0
    }
  }

  @VisibleForTesting
  Set<Subscriber> getSubscribersForTesting(Class<?> eventType) {

   * write.
   *
   * 2. visibility of the writes to an afterDone() call triggered by cancel():
   *
   * Since these fields are non-final that means that TimeoutFuture is not being 'safely published',
   * thus a motivated caller may be able to expose the reference to another thread that would then
   * call cancel() and be unable to cancel the delegate.

    checkState(this.removalListener == null);

    // safely limiting the kinds of caches this can produce
    @SuppressWarnings("unchecked")
    CacheBuilder<K1, V1> me = (CacheBuilder<K1, V1>) this;
    me.removalListener = checkNotNull(listener);
    return me;
  }

  // Make a safe contravariant cast now so we don't have to do it over and over.
  @SuppressWarnings("unchecked")

    fakePool.runAll();
    assertEquals(2, totalCalls.get());
    // Queue is empty so no runner should be scheduled.
    assertFalse(fakePool.hasNext());

    // Check that execute can be safely repeated
    e.execute(intCounter);
    e.execute(intCounter);
    e.execute(intCounter);
    // No change yet.
    assertEquals(2, totalCalls.get());
    fakePool.runAll();

 * evicted or manually invalidated. The common way to build instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null
 * @param <V> the type of the cache's values, which are not permitted to be null

     * safe to read even when the Entry object is unsafely published. But with a mutable graph, the
     * Entry object is likely to have a non-final value field, which is not safe to read when
     * unsafely published. (The Entry object might even be newly created by each iterator.next()
     * call, so we can't assume that writes to the Entry have been safely published by some other
     * synchronization actions.)

            });

            csvWriter.flush();
        } catch (final IOException e) {
            logger.warn("Failed to write a sugget elevate word.", e);
        }
    }

    /**
     * Safely retrieves a value from a list at the specified index, handling bounds checking
     * and cleaning up quoted strings.
     *
     * @param list the list to retrieve the value from

    }
    return false;
  }

  /**
   * Returns a "Java hash code" for this {@code HashCode} instance; this is well-defined (so, for
   * example, you can safely put {@code HashCode} instances into a {@code HashSet}) but is otherwise
   * probably not what you want to use.
   */
  @Override
  public final int hashCode() {

   * service listeners}. This is extracted into its own object so that {@link ServiceListener} could
   * be made {@code static} and its instances can be safely constructed and added in the {@link
   * ServiceManager} constructor without having to close over the partially constructed {@link
   * ServiceManager} instance (i.e. avoid leaking a pointer to {@code this}).
   */