} catch (Throwable t) {
      /*
       * This is not one of AppEngine's allowed classes, so even in Sun JDKs, this can fail with
       * a NoClassDefFoundError. Other apps might deny access to sun.misc packages.
       */
      return null;
    }
  }

  /**
   * Returns the Method that can be used to resolve an individual StackTraceElement, or null if that

import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * GWT implementation of {@link ImmutableSet} that forwards to another {@code Set} implementation.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ForwardingImmutableSet<E> extends ImmutableSet<E> {
  private final transient Set<E> delegate;

 * limitations under the License.
 */

package com.google.common.collect;

import java.util.HashMap;

/**
 * GWT emulation of {@link RegularImmutableBiMap}.
 *
 * @author Jared Levy
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial")
class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
  static final RegularImmutableBiMap<Object, Object> EMPTY =

import java.util.Arrays;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Generators of various {@link com.google.common.collect.BiMap}s and derived collections.
 *
 * @author Jared Levy
 * @author Hayward Chan
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class BiMapGenerators {
  public static class ImmutableBiMapGenerator extends TestStringBiMapGenerator {
    @Override

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code retainAll} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible

     * anything interesting under most environments. Still, we can run it (except for Android, at
     * least old versions), so we mostly do. This is useful because we don't actually run our CI on
     * Windows under Java 8, at least as of this writing.
     *
     * Under Windows in particular, we want to test that:
     *
     * - Under Java 9+, createTempDir() succeeds because it can look up the *real* username, rather

 *       The generated suite for {@code FooTest} ends up containing {@code FooTest} itself plus some
 *       other tests. We want to exclude the other tests (which Android can't handle) while
 *       continuing to run {@code FooTest} itself. This is exactly what happens with {@code
 *       AndroidIncompatible}. But I'm not sure what would happen if we annotated the {@code

  2. All contributions must be licensed Apache 2.0 and all files must have a
     copy of the boilerplate license comment (can be copied from an existing
     file).
  3. Files should be formatted according to Google's [Java style guide][].
  4. Please squash all commits for a change into a single commit (this can be
     done using `git rebase -i`). Do your best to have a
     [well-formed commit message][] for the change.

  //    guard.leave(), but that's a little odd as well because the
  //    guard doesn't have anything to do with leaving. You can't
  //    really enforce that the guard you're leaving is the same one
  //    you entered with, and it doesn't actually matter.
  //
  // 2. Since you can enter the monitor without a guard at all, some
  //    places you'll have monitor.enter()/monitor.leave() and other

          public void run() {
            do {
              // We can't have a GOLDEN_NOT_PRESENT_KEY because false positives are
              // possible! It's false negatives that can't happen.
              assertThat(bloomFilter.mightContain(GOLDEN_PRESENT_KEY)).isTrue();

              int key = getNonGoldenRandomKey();
              // We can't check that the key is mightContain() == false before the