.put(
              ConcurrentModificationException.class,
              e -> e instanceof ConcurrentModificationException)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)

  }

  /**
   * Marks the given step final, waits for it to be finished, and returns the value.
   *
   * @throws ExecutionException if the step failed
   * @throws CancellationException if the step was cancelled
   */
  abstract <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException;

  /** Marks the given step final, cancels it, and waits for the cancellation to happen. */

    throwException = true;

    // Start up the task and unblock the latch to finish the task.
    exec.execute(task);
    runLatch.await();
    taskLatch.countDown();

    ExecutionException e = assertThrows(ExecutionException.class, () -> task.get(5, SECONDS));
    assertEquals(IllegalStateException.class, e.getCause().getClass());

    assertTrue(listenerLatch.await(5, SECONDS));
    assertTrue(task.isDone());

   *       Futures#getUnchecked}.
   * </ul>
   *
   * @throws ExecutionException if the computation threw an exception
   * @throws CancellationException if the computation was cancelled
   */
  @CanIgnoreReturnValue
  @ParametricNullness
  public static <V extends @Nullable Object> V getUninterruptibly(Future<V> future)
      throws ExecutionException {
    boolean interrupted = false;
    try {
      while (true) {

  public void testFutureGetThrowsRuntimeException() throws Exception {
    BadFuture badInput = new BadFuture(immediateFuture(20));
    ListenableFuture<String> chain = buildChainingFuture(badInput);
    ExecutionException e = assertThrows(ExecutionException.class, () -> chain.get());
    assertSame(RuntimeException.class, e.getCause().getClass());
  }

  /** Proxy to throw a {@link RuntimeException} out of the {@link #get()} method. */

import org.jspecify.annotations.Nullable;

/**
 * {@link Error} variant of {@link java.util.concurrent.ExecutionException}. As with {@code
 * ExecutionException}, the error's {@linkplain #getCause() cause} comes from a failed task,
 * possibly run in another thread. That cause should itself be an {@code Error}; if not, use {@code
 * ExecutionException} or {@link UncheckedExecutionException}. This allows the client code to

          .put(
              ConcurrentModificationException.class,
              e -> e instanceof ConcurrentModificationException)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)

          .put(
              ConcurrentModificationException.class,
              e -> e instanceof ConcurrentModificationException)
          .put(ExecutionException.class, e -> e instanceof ExecutionException)
          .put(IllegalArgumentException.class, e -> e instanceof IllegalArgumentException)
          .put(IllegalStateException.class, e -> e instanceof IllegalStateException)

    ScheduledExecutorService executor = newScheduledThreadPool(1);
    try {
      FluentFuture<?> f =
          FluentFuture.from(SettableFuture.create()).withTimeout(0, SECONDS, executor);
      ExecutionException e = assertThrows(ExecutionException.class, () -> f.get());
      assertThat(e).hasCauseThat().isInstanceOf(TimeoutException.class);
    } finally {
      executor.shutdown();
    }
  }

  public void testFutureGetThrowsRuntimeException() throws Exception {
    BadFuture badInput = new BadFuture(immediateFuture(20));
    ListenableFuture<String> chain = buildChainingFuture(badInput);
    ExecutionException e = assertThrows(ExecutionException.class, () -> chain.get());
    assertSame(RuntimeException.class, e.getCause().getClass());
  }

  /** Proxy to throw a {@link RuntimeException} out of the {@link #get()} method. */