.isFalse();
    assertEquals(1, Booleans.asList(ARRAY_FALSE_TRUE).lastIndexOf(true));
    List<Boolean> reference = Booleans.asList(ARRAY_FALSE);
    assertEquals(Booleans.asList(ARRAY_FALSE), reference);
    // Explicitly call `equals`; `assertEquals` might return fast
    assertThat(reference.equals(reference)).isTrue();
  }

  public void testAsListHashcode() {
    assertThat(Booleans.asList(EMPTY).hashCode()).isEqualTo(1);

        .isFalse();
    assertEquals(1, Booleans.asList(ARRAY_FALSE_TRUE).lastIndexOf(true));
    List<Boolean> reference = Booleans.asList(ARRAY_FALSE);
    assertEquals(Booleans.asList(ARRAY_FALSE), reference);
    // Explicitly call `equals`; `assertEquals` might return fast
    assertThat(reference.equals(reference)).isTrue();
  }

  public void testAsListHashcode() {
    assertThat(Booleans.asList(EMPTY).hashCode()).isEqualTo(1);

/**
 * An immutable object that may contain a non-null reference to another object. Each instance of
 * this type either contains a non-null reference, or contains nothing (in which case we say that
 * the reference is "absent"); it is never said to "contain {@code null}".
 *
 * <p>A non-null {@code Optional<T>} reference can be used as a replacement for a nullable {@code T}

    @ParametricNullness private final T reference;

    private Wrapper(Equivalence<? super @NonNull T> equivalence, @ParametricNullness T reference) {
      this.equivalence = checkNotNull(equivalence);
      this.reference = reference;
    }

    /** Returns the (possibly null) reference wrapped by this instance. */
    @ParametricNullness
    public T get() {
      return reference;
    }

    /**

    @ParametricNullness private final T reference;

    private Wrapper(Equivalence<? super @NonNull T> equivalence, @ParametricNullness T reference) {
      this.equivalence = checkNotNull(equivalence);
      this.reference = reference;
    }

    /** Returns the (possibly null) reference wrapped by this instance. */
    @ParametricNullness
    public T get() {
      return reference;
    }

    /**

      Preconditions.checkState(valueRef instanceof Reference);
      Reference<V> ref = (Reference<V>) valueRef;
      if (ref != null) {
        ref.clear();
      }
    }
  }

  /**
   * Poke into the Cache internals to simulate garbage collection of the given key. This assumes
   * that the given entry is a weak or soft reference, and throws an IllegalStateException if that
   * assumption does not hold.

    Integer[] array1Tmp = array1;
    Object[] reference = list.toArray(array1Tmp);

    Object[] target = ObjectArrays.toArrayImpl(list, array2);

    assertEquals(reference.getClass(), target.getClass());
    assertTrue(Arrays.equals(reference, target));
    assertTrue(Arrays.equals(reference, target));

    Object[] expectedArray1 = expectModify ? reference : starting;

        map.put(keyOne, valueOne);
        ReferenceEntry<Object, Object> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));

        map.put(keyOne, valueOne);
        ReferenceEntry<Object, Object> entry = segment.getEntry(keyOne, hashOne);

        @SuppressWarnings("unchecked")
        Reference<Object> reference = (Reference<Object>) entry;
        reference.enqueue();

        map.put(keyTwo, valueTwo);
        assertFalse(map.containsKey(keyOne));
        assertFalse(map.containsValue(valueOne));

@SuppressWarnings("serial")
class RegularImmutableBiMap<K, V> extends ImmutableBiMap<K, V> {
  static final RegularImmutableBiMap<Object, Object> EMPTY =
      new RegularImmutableBiMap<Object, Object>();

  // This reference is used both by the GWT compiler to infer the elements
  // of the lists that needs to be serialized.
  private ImmutableBiMap<V, K> inverse;