* already complete, we would not initialize the subclass before calling {@link
   * #collectValueFromNonCancelledFuture}. As this is called after the subclass is constructed,
   * we're guaranteed to have properly initialized the subclass.
   */
  final void init() {
    /*

              @Override
              public V setValue(V value) {
                /*
                 * The cast is safe because of the containsKey check above. (Well, it's possible for
                 * the map to change between that call and this one. But if that happens, the
                 * behavior is undefined because of the concurrent mutation.)
                 *

      // permitted not to throw because it would be a no-op
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_KEY_QUERIES)
  public void testReplace_absentNullKeyUnsupported() {
    try {
      getMap().replace(null, v3());
    } catch (NullPointerException tolerated) {
      // permitted not to throw because it would be a no-op
    }
    expectUnchanged();
  }

      // permitted not to throw because it would be a no-op
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_KEY_QUERIES)
  public void testReplace_absentNullKeyUnsupported() {
    try {
      getMap().replace(null, v3());
    } catch (NullPointerException tolerated) {
      // permitted not to throw because it would be a no-op
    }
    expectUnchanged();
  }

 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,

            thread.start();
        }
    }

    void tryClose() {
        synchronized (LOCK) {

            /* Yes, there is the potential to drop packets
             * because we might close the socket during a
             * request. However the chances are slim and the
             * retry code should ensure the overall request
             * is serviced. The alternative complicates things

 * family. <b>Avoid</b> creating a mock or stub {@code Future}. Mock and stub implementations are
 * fragile because they assume that only certain methods will be called and because they often
 * implement subtleties of the API improperly.
 *
 * <p><b>Custom implementation</b>: Avoid implementing {@code ListenableFuture} from scratch. If you

                    break;
                }
            } catch (ResourceDoesNotExistException e) {
                // This one we will eat when looking through remote repositories
                // because we want to cycle through them all before squawking.

                logger.debug(
                        "Unable to find artifact " + artifact.getId() + " in repository " + repository.getId() + " ("

So, the frontend (that runs in the browser) would try to reach `/openapi.json` and wouldn't be able to get the OpenAPI schema.

Because we have a proxy with a path prefix of `/api/v1` for our app, the frontend needs to fetch the OpenAPI schema at `/api/v1/openapi.json`.

```mermaid
graph LR

browser("Browser")

   * the discussion in the {@link ListenableFuture#addListener ListenableFuture.addListener}
   * documentation.
   */
  public void add(Runnable runnable, Executor executor) {
    // Fail fast on a null. We throw NPE here because the contract of Executor states that it throws
    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");