* exception's creation.
   *
   * @since 19.0
   * @deprecated This method is equivalent to {@link Throwable#getStackTrace()} on JDK versions past
   *     JDK 8 and on all Android versions. Use {@link Throwable#getStackTrace()} directly, or where
   *     possible use the {@code java.lang.StackWalker.walk} method introduced in JDK 9.
   */
  @Deprecated
  @J2ktIncompatible

   * exception's creation.
   *
   * @since 19.0
   * @deprecated This method is equivalent to {@link Throwable#getStackTrace()} on JDK versions past
   *     JDK 8 and on all Android versions. Use {@link Throwable#getStackTrace()} directly, or where
   *     possible use the {@code java.lang.StackWalker.walk} method introduced in JDK 9.
   */
  @Deprecated
  @J2ktIncompatible

   * so that we get partial compile-time checking.)
   *
   * <p>This workaround should be removed at a distant future time when we no longer support Java
   * versions earlier than 8.
   */
  @SuppressWarnings("removal") // b/318391980
  private static final class TypeVariableInvocationHandler implements InvocationHandler {

    Collection<E> siblingCollection = new ArrayList<>();
    siblingCollection.add(sampleElement);

    Collection<E> copy = new ArrayList<>();
    // Avoid copy.addAll(collection), which runs afoul of an Android bug in older versions:
    // http://b.android.com/72073 http://r.android.com/98929
    Iterators.addAll(copy, collection.iterator());

    try {
      collection.add(sampleElement);

    putEdge(N2, N1);
    assertThat(graph.outDegree(N1)).isEqualTo(3);
  }

  // Stable order tests

  // Note: Stable order means that the ordering doesn't change between iterations and versions.
  // Ideally, the ordering in test should never be updated.
  @Test
  public void stableIncidentEdgeOrder_edges_returnsInStableOrder() {

    putEdge(N1, N2);
    assertThat(graph.outDegree(N1)).isEqualTo(2);
  }

  // Stable order tests

  // Note: Stable order means that the ordering doesn't change between iterations and versions.
  // Ideally, the ordering in test should never be updated.
  @Test
  public void stableIncidentEdgeOrder_edges_returnsInStableOrder() {

  /**
   * Gets a byte array representation of this instance.
   *
   * <p><b>Note:</b> No guarantees are made regarding stability of the representation between
   * versions.
   */
  public byte[] toByteArray() {
    ByteBuffer buff = ByteBuffer.allocate(BYTES).order(ByteOrder.LITTLE_ENDIAN);
    writeTo(buff);
    return buff.array();
  }

  /**

 *       wait();
 *     }
 *     value = newValue;
 *     notifyAll();
 *   }
 * }
 * }</pre>
 *
 * <h3>{@code ReentrantLock}</h3>
 *
 * <p>This version is much more verbose than the {@code synchronized} version, and still suffers
 * from the need for the programmer to remember to use {@code while} instead of {@code if}. However,

    putEdge(N1, N2);
    assertThat(graph.outDegree(N1)).isEqualTo(2);
  }

  // Stable order tests

  // Note: Stable order means that the ordering doesn't change between iterations and versions.
  // Ideally, the ordering in test should never be updated.
  @Test
  public void stableIncidentEdgeOrder_edges_returnsInStableOrder() {

 *   <li>{@code java.util.Optional} has the additional methods {@code ifPresent}, {@code filter},
 *       {@code flatMap}, and {@code orElseThrow}.
 *   <li>{@code java.util} offers the primitive-specialized versions {@code OptionalInt}, {@code
 *       OptionalLong} and {@code OptionalDouble}, the use of which is recommended; Guava does not
 *       have these.
 * </ul>
 *