return pickInstance(Charset.availableCharsets().values(), Charsets.UTF_8);
  }

  @Generates
  Locale generateLocale() {
    return pickInstance(Locale.getAvailableLocales(), Locale.US);
  }

  @Generates
  Currency generateCurrency() {
    return pickInstance(Currency.getAvailableCurrencies(), Currency.getInstance(Locale.US));
  }

  @Empty
  <T> Optional<T> generateJavaOptional() {
    return Optional.empty();

import java.lang.reflect.Method;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Queue;
import java.util.Set;

/**
 * Utilities for collecting and validating tester requirements from annotations.
 *
 * @author George van den Driessche
 */

import java.lang.reflect.Method;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import junit.framework.TestSuite;

import com.google.common.testing.NullPointerTester.Visibility;
import com.google.common.util.concurrent.RateLimiter.SleepingStopwatch;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.List;
import java.util.Locale;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.mockito.Mockito;

/**
 * Tests for RateLimiter.
 *
 * @author Dimitris Andreou
 */

import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Locale;
import javax.annotation.CheckForNull;

/**
 * Static utility methods pertaining to {@link InetAddress} instances.
 *
 * <p><b>Important note:</b> Unlike {@code InetAddress.getByName()}, the methods of this class never

    // racy single-check idiom, this is safe because Optional is immutable.
    Optional<Charset> local = parsedCharset;
    if (local == null) {
      String value = null;
      local = Optional.absent();
      for (String currentValue : parameters.get(CHARSET_ATTRIBUTE)) {
        if (value == null) {
          value = currentValue;
          local = Optional.of(Charset.forName(value));
        } else if (!value.equals(currentValue)) {

      checkValidState(cache);

      assertThrows(NullPointerException.class, () -> entry.setValue(null));
      checkValidState(cache);
    }
  }

  /* ---------------- Local utilities -------------- */

  /** Most of the tests in this class run against every one of these caches. */
  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache

    checkNotNull(fromKey);
    return newView(sortedDelegate.tailMap(fromKey));
  }

  public ImmutableSortedMap<K, V> tailMap(K fromKeyParam, boolean inclusive) {
    // Declare a "true" local variable so that the Checker Framework will infer nullness.
    K fromKey = fromKeyParam;
    checkNotNull(fromKey);
    if (!inclusive) {
      fromKey = higher(fromKey);
      if (fromKey == null) {

 */
@GwtIncompatible // not worth using in GWT for now
@ElementTypesAreNonnullByDefault
class CompactHashSet<E extends @Nullable Object> extends AbstractSet<E> implements Serializable {
  // TODO(user): cache all field accesses in local vars

  /** Creates an empty {@code CompactHashSet} instance. */
  public static <E extends @Nullable Object> CompactHashSet<E> create() {
    return new CompactHashSet<>();
  }

  /**