import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.util.Collections;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/** Implementation of an {@link Optional} not containing a reference. */
@GwtCompatible
final class Absent<T> extends Optional<T> {
  static final Absent<Object> INSTANCE = new Absent<>();

import com.google.common.collect.ImmutableSet;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import org.jspecify.annotations.NullUnmarked;

/**
 * @author Colin Decker
 */
@NullUnmarked
public class TestInputStream extends FilterInputStream {

  private final ImmutableSet<TestOption> options;
  private boolean closed;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.Multisets.UnmodifiableMultiset;
import java.util.Collections;
import java.util.Comparator;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Multisets#unmodifiableSortedMultiset(SortedMultiset)} for GWT.
 *
 * @author Louis Wasserman
 */

import com.google.errorprone.annotations.CheckReturnValue;
import java.util.concurrent.AbstractExecutorService;
import java.util.concurrent.Callable;
import java.util.concurrent.RunnableFuture;
import org.jspecify.annotations.Nullable;

/**
 * Abstract {@link ListeningExecutorService} implementation that creates {@link ListenableFuture}
 * instances for each {@link Runnable} and {@link Callable} submitted to it. These tasks are run

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.BiMap;
import com.google.common.collect.testing.SampleElements;
import java.util.List;
import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;

/**
 * Implementation helper for {@link TestBiMapGenerator} for use with bimaps of strings.
 *
 * @author Chris Povirk
 * @author Jared Levy
 * @author George van den Driessche

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.nio.charset.Charset;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Unit test for {@link Charsets}.
 *
 * @author Mike Bostock
 */
@GwtCompatible
@NullUnmarked
public class CharsetsTest extends TestCase {

  @J2ktIncompatible

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.Spliterator;
import java.util.function.Consumer;
import org.jspecify.annotations.Nullable;

/**
 * {@code keySet()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible

 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import org.jspecify.annotations.Nullable;

/**
 * Skeletal implementation of {@link ImmutableSortedSet#descendingSet()}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.testing.TearDownAccepter;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;
import org.jspecify.annotations.NullUnmarked;

/**
 * Utilities for performing thread interruption in tests
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible

import static java.util.Collections.singleton;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.MapInterfaceTest;
import java.util.Collection;
import java.util.Map;
import org.jspecify.annotations.NullMarked;

/**
 * Test {@code TreeMultimap.asMap().subMap()} with {@link MapInterfaceTest}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked