E[] elements = createSamplesArray();
    E duplicate = elements[(elements.length / 2) - 1];
    elements[(elements.length / 2) + 1] = duplicate;
    return new ArrayWithDuplicate<>(elements, duplicate);
  }

  // Helper methods to improve readability of derived classes

  protected int getNumElements() {
    return getSubjectGenerator().getCollectionSize().getNumElements();
  }

    otherwise. Do not persist these and assume they can be read by a future
    version of the library.

5.  Our classes are not designed to protect against a malicious caller. You
    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17

import com.google.common.base.Objects;
import com.google.common.primitives.Ints;
import java.util.Arrays;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Helper classes and static methods for implementing compact hash-based collections.
 *
 * @author Jon Noack
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class CompactHashing {
  private CompactHashing() {}

import com.google.common.base.Objects;
import com.google.common.primitives.Ints;
import java.util.Arrays;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Helper classes and static methods for implementing compact hash-based collections.
 *
 * @author Jon Noack
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class CompactHashing {
  private CompactHashing() {}

   * identifier} as the bus's name for logging purposes.
   *
   * @param identifier short name for the bus, for logging purposes.
   * @param executor Executor to use to dispatch events. It is the caller's responsibility to shut
   *     down the executor after the last event has been posted to this event bus.
   */
  public AsyncEventBus(String identifier, Executor executor) {

      throws Exception {
    // Make sure we are actually running with the expected helper implementation
    Class<?> abstractFutureClass = classLoader.loadClass(AbstractFuture.class.getName());
    Field helperField = abstractFutureClass.getDeclaredField("ATOMIC_HELPER");
    helperField.setAccessible(true);
    assertEquals(expectedHelperClassName, helperField.get(null).getClass().getSimpleName());

   * would declare a return type of `@Nullable T[]`. However, we've decided not to think too hard
   * about arrays for now, as they're a mess. (We previously discussed this in the review of
   * ObjectArrays, which is the main caller of this method.)
   */
  static <T extends @Nullable Object> T[] newArray(T[] reference, int length) {
    T[] empty = reference.length == 0 ? reference : Arrays.copyOf(reference, 0);
    return Arrays.copyOf(empty, length);

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.ScheduledFuture;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Helper interface to implement both {@link ListenableFuture} and {@link ScheduledFuture}.
 *
 * @author Anthony Zana
 * @since 15.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

 */

package com.google.common.collect.testing.google;

import static junit.framework.Assert.fail;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multimap;

/**
 * Helper methods/assertions for use with {@code com.google.common.collect} types.
 *
 * @author Colin Decker
 */
@GwtCompatible
final class GoogleHelpers {

  private GoogleHelpers() {}

 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

/**
 * Implementation helper for {@link TestMapGenerator} for use with maps of strings.
 *
 * @author Chris Povirk
 * @author Jared Levy
 * @author George van den Driessche
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault