assertThrows(NullPointerException.class, () -> Optional.of(null));
  }

  public void testFromNullable() {
    Optional<String> optionalName = Optional.fromNullable("bob");
    assertEquals("bob", optionalName.get());
  }

  public void testFromNullable_null() {
    // not promised by spec, but easier to test
    assertSame(Optional.absent(), Optional.fromNullable(null));
  }

  public void testIsPresent_no() {

     * allowing the CAS below to succeed.
     */
    Thread currentThread = Thread.currentThread();
    if (!compareAndSet(null, currentThread)) {
      return; // someone else has run or is running.
    }

    boolean run = !isDone();
    T result = null;
    Throwable error = null;
    try {
      if (run) {
        result = runInterruptibly();

  public void testSetCount_addNull_nullSupported() {
    assertSetCount(null, 1);
  }

  @CollectionFeature.Require(value = SUPPORTS_ADD, absent = ALLOWS_NULL_VALUES)
  public void testSetCount_addNull_nullUnsupported() {
    assertThrows(NullPointerException.class, () -> setCountNoCheckReturnValue(null, 1));
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)

            eventCatapult.fire(ExecutionEvent.Type.SessionEnded, session, null);
        }
    }

    public List<TaskSegment> calculateTaskSegments(MavenSession session) throws Exception {

        MavenProject rootProject = session.getTopLevelProject();

        List<String> tasks = requireNonNull(session.getGoals()); // session never returns null, but empty list

        if (tasks.isEmpty()

        return builder()
                .session(requireNonNull(session, "session cannot be null"))
                .coordinates(requireNonNull(coordinates, "coordinates cannot be null"))
                .build();
    }

    @Nonnull
    static ArtifactResolverRequest build(
            @Nonnull Session session,

    Iterator<Entry<E>> entryIterator = entryIterator();
    return entryIterator.hasNext() ? entryIterator.next() : null;
  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    Iterator<Entry<E>> entryIterator = descendingEntryIterator();
    return entryIterator.hasNext() ? entryIterator.next() : null;
  }

  @Override
  public @Nullable Entry<E> pollFirstEntry() {

        for (Vertex v : children) {
            DfsState state = stateMap.putIfAbsent(v, DfsState.VISITING);
            if (state == null) {
                cycle.addLast(v.label);
                List<String> ret = visitCycle(v.children, stateMap, cycle);
                if (ret != null) {
                    return ret;
                }
                cycle.removeLast();
                stateMap.put(v, DfsState.VISITED);

  private static final Object OBJECT = new Object();

  public void testNewReference() throws Exception {
    assertEquals(null, Atomics.newReference().get());
  }

  public void testNewReference_withInitialValue() throws Exception {
    assertEquals(null, Atomics.newReference(null).get());
    assertEquals(OBJECT, Atomics.newReference(OBJECT).get());
  }

  public void testNewReferenceArray_withLength() throws Exception {

     *
     * @param session The repository session, must not be {@code null}.
     * @param artifactCoordinates The artifact coordinates for which the version needs to be resolved, must not be {@code null}
     * @return The version result, never {@code null}.
     * @throws VersionResolverException If the metaversion could not be resolved.
     */
    @Nonnull

              "options": {
                "match": "null",
                "result": {
                  "text": "N/A"
                }
              },
              "type": "special"
            }
          ],
          "thresholds": {
            "mode": "absolute",
            "steps": [
              {
                "color": "green",
                "value": null
              },
              {