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>

    // 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 =

    for (int i = 0; i < stimuli.length; i++) {
      try {
        stimuli[i].executeAndCompare(reference, target);
        verify(reference.getElements());
      } catch (AssertionFailedError cause) {
        Helpers.fail(cause, "failed with stimuli " + subListCopy(stimuli, i + 1));
      }
    }
  }

  private static List<Object> subListCopy(Object[] source, int size) {
    final Object[] copy = new Object[size];

 *     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>

        .withSetUp(setUp)
        .withTearDown(tearDown)
        .createTestSuite();
  }

  private static LinkageError newLinkageError(Throwable cause) {
    LinkageError error = new LinkageError(cause.toString());
    error.initCause(cause);
    return error;
  }

        .withSetUp(setUp)
        .withTearDown(tearDown)
        .createTestSuite();
  }

  private static LinkageError newLinkageError(Throwable cause) {
    LinkageError error = new LinkageError(cause.toString());
    error.initCause(cause);
    return error;
  }

    assertThat(future.set(1)).isTrue();
    assertSuccessful(future, 1);
  }

  public void testFailed() throws Exception {
    Exception cause = new Exception();
    assertThat(future.setException(cause)).isTrue();
    assertFailed(future, cause);
  }

  public void testCanceled() throws Exception {
    assertThat(future.cancel(false /* mayInterruptIfRunning */)).isTrue();
    assertCancelled(future, false);