node.thread = null; // mark as 'deleted'
    restart:
    while (true) {
      Waiter pred = null;
      Waiter curr = waitersField;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.

                artifacts, projectArtifact.artifact, null, null, null, source, filter, Collections.emptyList(), null);
    }

    private ArtifactResolutionResult collect(ArtifactSpec a) throws ArtifactResolutionException {
        return artifactCollector.collect(
                Collections.singleton(a.artifact),
                projectArtifact.artifact,
                null,
                null,
                null,

    assertEquals("correct", f.apply(new Object()));
    assertEquals("correct", f.apply(null));

    Function<@Nullable Object, @Nullable String> g = Functions.constant(null);
    assertEquals(null, g.apply(2));
    assertEquals(null, g.apply(null));

    new EqualsTester()
        .addEqualityGroup(f, Functions.constant("correct"))

   *
   * @param escaper the non-null escaper to test
   */
  public static void assertBasic(Escaper escaper) throws IOException {
    // Escapers operate on characters: no characters, no escaping.
    Assert.assertEquals("", escaper.escape(""));
    // Assert that escapers throw null pointer exceptions.
    try {
      escaper.escape((String) null);

interface ModelCacheTag<T> {

    /**
     * Gets the name of the tag.
     *
     * @return The name of the tag, must not be {@code null}.
     */
    String getName();

    /**
     * Gets the type of data associated with this tag.
     *
     * @return The type of data, must not be {@code null}.
     */
    Class<T> getType();

    /**

   *
   * @param escaper the non-null escaper to test
   */
  public static void assertBasic(Escaper escaper) throws IOException {
    // Escapers operate on characters: no characters, no escaping.
    Assert.assertEquals("", escaper.escape(""));
    // Assert that escapers throw null pointer exceptions.
    try {
      escaper.escape((String) null);

  public void testPutIfAbsent_nullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> getMap().putIfAbsent(null, v3()));
    expectUnchanged();
    expectNullKeyMissingWhenNullKeysUnsupported(
        "Should not contain null key after unsupported putIfAbsent(null, value)");
  }

  @MapFeature.Require(value = SUPPORTS_PUT, absent = ALLOWS_NULL_VALUES)

    private Map<TransferResource, Long> downloads = new ConcurrentHashMap<>();

    private int lastLength;

    public ConsoleTransferListener() {
        this(null);
    }

    public ConsoleTransferListener(PrintStream out) {
        this.out = (out != null) ? out : System.out;
    }

    @Override
    public void transferInitiated(TransferEvent event) {

        this(null, null, null, message);
    }

    /**
     * @deprecated use {@link #DuplicateProjectException(String, File, File, String)}
     */
    @Deprecated
    public DuplicateProjectException(String message, Exception e) {
        super(message, e);
        this.projectId = null;
        this.existingProjectFile = null;
        this.conflictingProjectFile = null;
    }

    }

    public List<String> getExportedPackages() {
        if (exportedPackages == null) {
            exportedPackages = new ArrayList<>();
        }

        return exportedPackages;
    }

    public void setExportedPackages(List<String> exportedPackages) {
        if (exportedPackages == null) {
            this.exportedPackages = null;
        } else {
            this.exportedPackages = new ArrayList<>(exportedPackages);