@GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    @SuppressWarnings("unchecked")
    // reading data stored by writeObject
    Comparator<? super E> comparator = (Comparator<? super E>) requireNonNull(stream.readObject());
    Serialization.getFieldSetter(AbstractSortedMultiset.class, "comparator").set(this, comparator);

  }

  /**
   * Used to randomize {@link #goodFastHash} instances, so that programs which persist anything
   * dependent on the hash codes they produce will fail sooner.
   */
  @SuppressWarnings("GoodTime") // reading system time without TimeSource
  static final int GOOD_FAST_HASH_SEED = (int) System.currentTimeMillis();

  /**
   * Returns a hash function implementing the <a

    }
  }

  private void doTestExistsThrowsSecurityException() throws IOException, URISyntaxException {
    File file = null;
    // In Java 9, Logger may read the TZ database. Only disallow reading the class path URLs.
    final PermissionCollection readClassPathFiles =
        new FilePermission("", "read").newPermissionCollection();
    for (URL url : ClassPath.parseJavaClassPath()) {

            and .java files in c.g.c.collect.testModule, one that it doesn't[*]. Consequently,
            c.g.c.base.testModule transitively pulls in .java files from both modules while reading
            the module description of only the prod module. And the prod module doesn't inherit all
            the modules that the test module classes use, so we get errors.