* ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null
   * types (or if the type is a non-variable type, like {@code String}), then code should almost
   * never use this method, preferring instead to call {@code requireNonNull} so as to benefit from
   * its runtime check.
   *
   * <p>An example use case for this method is in implementing an {@code Iterator<T>} whose {@code

     *
     * @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);

    /**

  public <T extends @Nullable Object> T[] toArray(T[] other) {
    return ObjectArrays.toArrayImpl(this, other);
  }

  @Override
  public boolean contains(@Nullable Object object) {
    try {
      // This set never contains null.  We need to explicitly check here
      // because some comparator might throw NPE (e.g. the natural ordering).
      return object != null && sortedDelegate.contains(object);
    } catch (ClassCastException e) {

    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");
    // These have a combination of invalid length, unrecognized characters and wrong padding.

import static org.mockito.ArgumentMatchers.isNull;
import static org.mockito.ArgumentMatchers.same;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.junit.jupiter.api.BeforeEach;

    assertFalse(
        "Maps of different sizes should not be equal.", getMap().equals(newHashMap(moreEntries)));
  }

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

  private static <K, V> Map<K, V> newHashMap(
      Collection<? extends Entry<? extends K, ? extends V>> entries) {

      while (true) {
        /*
         * requireNonNull is safe because visitedNodes isn't cleared until this method calls
         * endOfData() (after which this method is never called again).
         */
        requireNonNull(visitedNodes);
        while (successorIterator.hasNext()) {
          N otherNode = successorIterator.next();
          if (!visitedNodes.contains(otherNode)) {

  /*
   * 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;

    /**
     * @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();

    /**