}

  enum Impl {
    NEW {
      @Override
      ExecutionListWrapper newExecutionList() {
        return new ExecutionListWrapper() {
          final ExecutionList list = new ExecutionList();

          @Override
          public void add(Runnable runnable, Executor executor) {
            list.add(runnable, executor);
          }

          @Override
          public void execute() {

  }

  @Override
  public void write(byte[] b, int off, int len) throws IOException {
    // Override slow FilterOutputStream impl
    out.write(b, off, len);
  }

  @Override
  public void writeBoolean(boolean v) throws IOException {
    ((DataOutputStream) out).writeBoolean(v);
  }

  @Override
  public void writeByte(int v) throws IOException {

  @Override
  public <T extends @NonNull B> @Nullable T getInstance(Class<T> type) {
    return trustedGet(TypeToken.of(type));
  }

  @Override
  public <T extends @NonNull B> @Nullable T getInstance(TypeToken<T> type) {
    return trustedGet(type.rejectTypeVariables());
  }

  @Override
  @CanIgnoreReturnValue
  public <T extends B> @Nullable T putInstance(

  private static class NonReflexiveObject {

    @Override
    public boolean equals(@Nullable Object o) {
      return false;
    }

    @Override
    public int hashCode() {
      return super.hashCode();
    }
  }

  /** Test class that returns true if the test object is null */
  private static class InvalidEqualsNullObject {

    @Override
    public boolean equals(@Nullable Object o) {

          @Override
          public boolean cancel(boolean interrupt) {
            return false;
          }

          @Override
          public boolean isDone() {
            return true;
          }

          @Override
          public boolean isCancelled() {
            return true; // BAD!!
          }

          @Override
          public String get() {

    }
  }

  @Override
  public @Nullable Entry<E> firstEntry() {
    return delegate().firstEntry();
  }

  /**
   * A sensible definition of {@link #firstEntry()} in terms of {@code entrySet().iterator()}.
   *
   * <p>If you override {@link #entrySet()}, you may wish to override {@link #firstEntry()} to
   * forward to this implementation.
   */
  protected @Nullable Entry<E> standardFirstEntry() {

    this.forward = forward;
  }

  @Override
  public int count(@Nullable Object element) {
    return forward.count(element);
  }

  @Override
  public @Nullable Entry<E> firstEntry() {
    return forward.lastEntry();
  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {
    return forward.size();
  }

        @Override
        public String getType() {
            return delegate.getType();
        }

        @Override
        public String findTool(String toolName) {
            return delegate.findTool(toolName);
        }

        @Override
        public org.apache.maven.api.toolchain.ToolchainModel getModel() {

      this.backingSortedSet = backingSortedSet;
    }

    @Override
    protected SortedSet<T> delegate() {
      return backingSortedSet;
    }

    @Override
    public boolean equals(@Nullable Object object) {
      return standardEquals(object);
    }

    @Override
    public int hashCode() {
      return standardHashCode();
    }

    @Override
    public boolean addAll(Collection<? extends T> collection) {

  public AbstractValueGraph() {}

  @Override
  public Graph<N> asGraph() {
    return new AbstractGraph<N>() {
      @Override
      public Set<N> nodes() {
        return AbstractValueGraph.this.nodes();
      }

      @Override
      public Set<EndpointPair<N>> edges() {
        return AbstractValueGraph.this.edges();
      }

      @Override
      public boolean isDirected() {