Multiset<N> successors = getReference(successorsReference);
    if (successors != null) {
      checkState(successors.add(node));
    }
  }

  private static <T> @Nullable T getReference(@Nullable Reference<T> reference) {
    return (reference == null) ? null : reference.get();
  }

import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Multimaps#filterEntries(Multimap, Predicate)}.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
class FilteredEntryMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimap<K, V> implements FilteredMultimap<K, V> {

      List<@Nullable String> listWithNulls = asList("a", null, "b");
      assertThrows(NullPointerException.class, () -> builder.addAll((List<String>) listWithNulls));
    }

    {
      ImmutableList.Builder<String> builder = ImmutableList.builder();
      Iterator<@Nullable String> iteratorWithNulls =
          Arrays.<@Nullable String>asList("a", null, "b").iterator();
      assertThrows(

   * not have been inserted consecutively.
   */
  private final @Nullable List<NodeConnection<N>> orderedNodeConnections;

  private int predecessorCount;
  private int successorCount;

  private DirectedGraphConnections(
      Map<N, Object> adjacentNodeValues,
      @Nullable List<NodeConnection<N>> orderedNodeConnections,
      int predecessorCount,
      int successorCount) {

import org.jspecify.annotations.Nullable;

/**
 * Tests for {@code GeneralRange}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public class GeneralRangeTest extends TestCase {
  private static final Ordering<@Nullable Integer> ORDERING =
      Ordering.<Integer>natural().<Integer>nullsFirst();

  private static final List<@Nullable Integer> IN_ORDER_VALUES =

import java.util.Set;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates map entries using sample keys and sample values.
 *
 * @author Jesse Wilson
 */
@GwtCompatible
@NullMarked
public abstract class TestMapEntrySetGenerator<
        K extends @Nullable Object, V extends @Nullable Object>
    implements TestSetGenerator<Map.Entry<K, V>> {
  private final SampleElements<K> keys;

 * @since 9.0 (in 1.0 as {@code ValueFuture})
 */
@GwtCompatible
public final class SettableFuture<V extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<V> {
  /**
   * Creates a new {@code SettableFuture} that can be completed or cancelled by a later method call.
   */
  public static <V extends @Nullable Object> SettableFuture<V> create() {
    return new SettableFuture<>();
  }

  @CanIgnoreReturnValue
  @Override

    boolean contains(@Nonnull Version version);

    /**
     * Returns the upper boundary of this range, or {@code null} if none.
     */
    @Nullable
    Boundary getUpperBoundary();

    /**
     * Returns the lower boundary of this range, or {@code null} if none.
     */
    @Nullable
    Boundary getLowerBoundary();

    /**
     * {@return the string representation of this version}
     */
    @Nonnull
    @Override

  }

  public void testCopyOf_nullArray() {
    assertThrows(NullPointerException.class, () -> copyOf((String[]) null));
  }

  public void testCopyOf_arrayContainingOnlyNull() {
    @Nullable String[] array = new @Nullable String[] {null};
    assertThrows(NullPointerException.class, () -> copyOf((String[]) array));
  }

  public void testCopyOf_collection_empty() {
    Collection<String> c = MinimalCollection.of();

    return super.toString();
  }

  @Override
  public boolean equals(@Nullable Object o) {
    assertTrue(Thread.holdsLock(mutex));
    return super.equals(o);
  }

  @Override
  public int hashCode() {
    assertTrue(Thread.holdsLock(mutex));
    return super.hashCode();
  }

  @Override
  public boolean add(@Nullable E o) {
    assertTrue(Thread.holdsLock(mutex));
    return super.add(o);
  }