assertEquals(comparator, elementSet.comparator());
  }

  public void testNullAcceptingComparator() throws Exception {
    Comparator<@Nullable String> comparator = Ordering.<String>natural().<String>nullsFirst();
    TreeMultiset<@Nullable String> ms = TreeMultiset.create(comparator);

    ms.add("b");
    ms.add(null);
    ms.add("a");
    ms.add("b");
    ms.add(null, 2);

// instead of using an AtomicReferenceFieldUpdater. This reference stores Thread instances
// and DONE/INTERRUPTED - they have a common ancestor of Runnable.
abstract class InterruptibleTask<T extends @Nullable Object>
    extends AtomicReference<@Nullable Runnable> implements Runnable {
  static {
    // Prevent rare disastrous classloading in first call to LockSupport.park.
    // See: https://bugs.openjdk.java.net/browse/JDK-8074773

import static java.lang.Math.min;

import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link UnicodeEscaper} that uses an array to quickly look up replacement characters for a given
 * code point. An additional safe range is provided that determines whether code points without

  }

  /**
   * @since 28.1
   */
  @Override
  public void merge(
      Range<K> range,
      @CheckForNull V value,
      BiFunction<? super V, ? super @Nullable V, ? extends @Nullable V> remappingFunction) {
    checkNotNull(range);
    checkNotNull(remappingFunction);

    if (range.isEmpty()) {
      return;
    }
    split(range.lowerBound);
    split(range.upperBound);

                      maximum: 4294967295
                      minimum: 0
                      nullable: true
                      type: integer
                    mirrorPercent:
                      maximum: 4294967295
                      minimum: 0
                      nullable: true
                      type: integer
                    mirrorPercentage:

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link Subscriber}.
 *
 * @author Cliff Biffle
 * @author Colin Decker
 */
public class SubscriberTest extends TestCase {

  private static final Object FIXTURE_ARGUMENT = new Object();

  private EventBus bus;
  private boolean methodCalled;
  private @Nullable Object methodArgument;

  @Override

import java.util.Collection;
import java.util.Set;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@code ForwardingSet}.
 *
 * @author Robert Konigsberg
 * @author Louis Wasserman
 */
public class ForwardingSetTest extends TestCase {

    @CheckForNull Comparator<? super V> valueComparator;
    @Nullable Object[] alternatingKeysAndValues;
    int size;
    boolean entriesUsed;
    /**
     * If non-null, a duplicate key we found in a previous buildKeepingLast() or buildOrThrow()
     * call. A later buildOrThrow() can simply report this duplicate immediately.
     */
    @Nullable DuplicateKey duplicateKey;

    /**

import org.checkerframework.checker.nullness.qual.Nullable;

/** Replacements for JUnit's {@code assertThrows} that work under GWT/J2CL. */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class ReflectionFreeAssertThrows {
  interface ThrowingRunnable {
    void run() throws Throwable;
  }

  interface ThrowingSupplier {
    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue

import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@code ForwardingList}.
 *
 * @author Robert Konigsberg
 * @author Louis Wasserman
 */
public class ForwardingListTest extends TestCase {