Throwable cause = e.getCause();
    if (cause == null) {
      throw e;
    }
    if (combineStackTraces) {
      StackTraceElement[] combined =
          ObjectArrays.concat(cause.getStackTrace(), e.getStackTrace(), StackTraceElement.class);
      cause.setStackTrace(combined);
    }
    if (cause instanceof Exception) {
      throw (Exception) cause;
    }
    if (cause instanceof Error) {

    public TwoArgConstructorException(String message, Throwable cause) {
      super(message, cause);
    }
  }

  public static final class TwoArgConstructorRuntimeException extends RuntimeException {
    public TwoArgConstructorRuntimeException(String message, Throwable cause) {
      super(message, cause);
    }
  }

  public static final class ExceptionWithPrivateConstructor extends Exception {

  }

  /**
   * Gets a {@code Throwable} cause chain as a list. The first entry in the list will be {@code
   * throwable} followed by its cause hierarchy. Note that this is a snapshot of the cause chain and
   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>

  }

  /**
   * Gets a {@code Throwable} cause chain as a list. The first entry in the list will be {@code
   * throwable} followed by its cause hierarchy. Note that this is a snapshot of the cause chain and
   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>

    return new RemovalNotification<>(key, value, cause);
  }

  private RemovalNotification(@CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
    super(key, value);
    this.cause = checkNotNull(cause);
  }

  /** Returns the cause for which the entry was removed. */
  public RemovalCause getCause() {
    return cause;
  }

  /**

    assertThat(expected).hasCauseThat().isEqualTo(cause);

    Object newValue = new Object();
    valueRef.set(newValue);
    assertSame(newValue, cache.getUnchecked(new Object()));
  }

  public void testGetUnchecked_unchecked() {
    final RuntimeException cause = new RuntimeException();
    final AtomicReference<Object> valueRef = new AtomicReference<>();
    LoadingCache<Object, Object> cache =

    // Hack to load AbstractFuture et. al. in a new classloader so that it re-reads the cancellation
    // cause system property.  This allows us to run with both settings of the property in one jvm
    // without resorting to even crazier hacks to reset static final boolean fields.
    System.setProperty("guava.concurrent.generate_cancellation_cause", "true");
    final String concurrentPackage = SettableFuture.class.getPackage().getName();
    classReloader =

    Throwable wrapper = e.getCause();
    if (wrapper instanceof WrapperException) {
      Throwable cause = wrapper.getCause();
      if (cause instanceof RuntimeException) {
        throw (RuntimeException) cause;
      } else if (cause instanceof Error) {
        throw (Error) cause;
      }
    }
    throw e;
  }

  @Override
  public V get() throws ExecutionException, InterruptedException {

 *     Guava 27.0
 */
public final class InternalFutures {
  /**
   * Usually returns {@code null} but, if the given {@code Future} has failed, may <i>optionally</i>
   * return the cause of the failure. "Failure" means specifically "completed with an exception"; it
   * does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:
   *
   * <ul>

    } catch (ExecutionException e) {
      builder.append("FAILURE, cause=[").append(e.getCause()).append("]");
    } catch (CancellationException e) {
      builder.append("CANCELLED");
    } catch (RuntimeException e) {
      builder.append("UNKNOWN, cause=[").append(e.getClass()).append(" thrown from get()]");
    }
  }

  private enum State {
    PENDING {