*
     * @param artifact The artifact whose available versions should be determined, must not be {@code null}.
     * @return The available versions of the artifact or an empty list if none, never {@code null}.
     * @since 3.0-alpha-3
     */
    List<String> findVersions(Artifact artifact);

    /**

  private final transient ConcurrentMap<E, AtomicInteger> countMap;

  /**
   * An instance created in {@link #readObject} to be returned from {@link #readResolve}. This field
   * is used only by those methods, and it is never set in a "normal" instance.
   *
   * <p>This class needs to write deserialized data into fields that are {@code final transient}.
   * Such writes will become impossible to perform in {@link #readObject} after JEP 500. Instead, we

 *
 * <ul>
 *   <li><b>Shallow immutability.</b> Elements can never be added, removed or replaced in this
 *       collection. This is a stronger guarantee than that of {@link
 *       Collections#unmodifiableCollection}, whose contents change whenever the wrapped collection
 *       is modified.
 *   <li><b>Null-hostility.</b> This collection will never contain a null element.

  /*
   * We access this field racily but safely. For discussion of a similar situation, see the comments
   * on the fields of TimeoutFuture. This field is slightly different from the fields discussed
   * there: cancel() never reads this field, only writes to it. That makes the race here completely
   * harmless, rather than just 99.99% harmless.
   */
  @LazyInit private @Nullable List<@Nullable Present<V>> values;

// it is no longer referenced, so it must be kept alive (see runtime.KeepAlive)
// until any memory allocated from it is no longer needed.
//
// An Arena must never be used concurrently by multiple goroutines.
type Arena struct {
	a unsafe.Pointer
}

// NewArena allocates a new arena.
func NewArena() *Arena {
	return &Arena{a: runtime_arena_newArena()}
}

  /*
   * We access this field racily but safely. For discussion of a similar situation, see the comments
   * on the fields of TimeoutFuture. This field is slightly different from the fields discussed
   * there: cancel() never reads this field, only writes to it. That makes the race here completely
   * harmless, rather than just 99.99% harmless.
   */
  @LazyInit private @Nullable List<@Nullable Present<V>> values;

    assertFalse(
        "Sets of different sizes should not be equal.",
        getSet().equals(MinimalSet.from(moreElements)));
  }

  public void testEquals_list() {
    assertFalse("A List should never equal a Set.", getSet().equals(copyToList(getSet())));
  }

    assertFalse(
        "Sets of different sizes should not be equal.",
        getSet().equals(MinimalSet.from(moreElements)));
  }

  public void testEquals_list() {
    assertFalse("A List should never equal a Set.", getSet().equals(copyToList(getSet())));
  }

    /**
     * @return dependency for this node
     */
    @Nullable
    Dependency getDependency();

    /**
     * Gets the child nodes of this node.
     *
     * @return the child nodes of this node, never {@code null}
     */
    @Nonnull
    List<Node> getChildren();

    /**
     * @return repositories of this node
     */
    @Nonnull
    List<RemoteRepository> getRemoteRepositories();

    /**

     * in the former case, this method can never return zero, while in the latter, it will return
     * zero if all occurrences of the element were since removed from the multiset.
     *
     * @return the count of the element; never negative
     */
    int getCount();

    /**
     * {@inheritDoc}
     *