*     .maximumSize(10000)
 *     .expireAfterWrite(Duration.ofMinutes(10))
 *     .removalListener(MY_LISTENER)
 *     .build(
 *         new CacheLoader<Key, Graph>() {
 *           public Graph load(Key key) throws AnyException {
 *             return createExpensiveGraph(key);
 *           }
 *         });
 * }</pre>
 *
 * <p>Or equivalently,
 *
 * <pre>{@code

    implements ClassToInstanceMap<B>, Serializable {

  /**
   * Returns a new {@code MutableClassToInstanceMap} instance backed by a {@link HashMap} using the
   * default initial capacity and load factor.
   */
  public static <B extends @Nullable Object> MutableClassToInstanceMap<B> create() {
    return new MutableClassToInstanceMap<>(new HashMap<Class<? extends @NonNull B>, B>());
  }

  /**

    // This class can make no hard guarantees.  The methods in this class are inherently flaky, but
    // we try hard to make them robust in practice.  We could additionally try to add in a system
    // load timeout multiplier.  Or we could try to use a CPU time bound instead of wall clock time
    // bound.  But these ideas are harder to implement.  We do not try to detect or handle a
    // user-specified -XX:+DisableExplicitGC.

 *     .maximumSize(10000)
 *     .expireAfterWrite(10, TimeUnit.MINUTES)
 *     .removalListener(MY_LISTENER)
 *     .build(
 *         new CacheLoader<Key, Graph>() {
 *           public Graph load(Key key) throws AnyException {
 *             return createExpensiveGraph(key);
 *           }
 *         });
 * }</pre>
 *
 * <p>Or equivalently,
 *
 * <pre>{@code

  public void testTransform_StackOverflow() throws Exception {
    {
      /*
       * Initialize all relevant classes before running the test, which may otherwise poison any
       * classes it is trying to load during its stack overflow.
       */
      SettableFuture<Object> root = SettableFuture.create();
      ListenableFuture<Object> unused = transform(root, identity(), directExecutor());
      root.set("foo");
    }

    assertEquals(2, result.size());

    // Now test values loaded from a stream.
    String props = "test\n second = 2\n Third item :   a short  phrase   ";

    testProp.load(new StringReader(props));

    result = Maps.fromProperties(testProp);
    assertEquals(4, result.size());
    assertEquals("true", result.get("first"));
    assertEquals("", result.get("test"));

    assertEquals(2, result.size());

    // Now test values loaded from a stream.
    String props = "test\n second = 2\n Third item :   a short  phrase   ";

    testProp.load(new StringReader(props));

    result = Maps.fromProperties(testProp);
    assertEquals(4, result.size());
    assertEquals("true", result.get("first"));
    assertEquals("", result.get("test"));

 *           // Services have been initialized and are healthy, start accepting requests...
 *         }
 *         public void failure(Service service) {
 *           // Something failed, at this point we could log it, notify a load balancer, or take
 *           // some other action.  For now we will just exit.
 *           System.exit(1);
 *         }
 *       },
 *       MoreExecutors.directExecutor());
 *

  public void testTransform_StackOverflow() throws Exception {
    {
      /*
       * Initialize all relevant classes before running the test, which may otherwise poison any
       * classes it is trying to load during its stack overflow.
       */
      SettableFuture<Object> root = SettableFuture.create();
      ListenableFuture<Object> unused = transform(root, identity(), directExecutor());
      root.set("foo");
    }

    @Override
    public void notifyNewValue(@CheckForNull V newValue) {
      if (newValue != null) {
        // The pending load was clobbered by a manual write.
        // Unblock all pending gets, and have them return the new value.
        set(newValue);
      } else {
        // The pending load was removed. Delay notifications until loading completes.
        oldValue = unset();
      }