static final Exception CHECKED_EXCEPTION = new Exception("mymessage");
  static final Future<String> FAILED_FUTURE_CHECKED_EXCEPTION =
      immediateFailedFuture(CHECKED_EXCEPTION);
  static final RuntimeException UNCHECKED_EXCEPTION = new RuntimeException("mymessage");
  static final Future<String> FAILED_FUTURE_UNCHECKED_EXCEPTION =
      immediateFailedFuture(UNCHECKED_EXCEPTION);

 *     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:

import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_CHECKED_EXCEPTION;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_ERROR;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_OTHER_THROWABLE;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_UNCHECKED_EXCEPTION;

        assertThrows(RuntimeException.class, () -> service.startAsync().awaitRunning());
    assertThat(e).hasCauseThat().isSameInstanceAs(exception);
    assertEquals(Service.State.FAILED, service.state());
  }

  public void testFunctionalStop_failed() {
    final Exception exception = new Exception("deliberate");
    AbstractIdleService service =
        new DefaultService() {
          @Override

        throw new RuntimeException(e);
      } catch (InvocationTargetException e) {
        throw Throwables.propagate(e.getCause());
      }
      assertEquals("Failed to forward to " + method, 1, called.get());
    }

    @Override
    public String toString() {
      return "dummy " + interfaceType.getSimpleName();
    }
  }

        throw new RuntimeException(e);
      } catch (InvocationTargetException e) {
        throw Throwables.propagate(e.getCause());
      }
      assertEquals("Failed to forward to " + method, 1, called.get());
    }

    @Override
    public String toString() {
      return "dummy " + interfaceType.getSimpleName();
    }
  }

    try {
      unicodeEscaper.escape("\uD800x\uDC00");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass
    }
    assertEquals("<lo><hi>", charEscaper.escape("\uDC00\uD800"));
    try {
      unicodeEscaper.escape("\uDC00\uD800");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass

    try {
      unicodeEscaper.escape("\uD800x\uDC00");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass
    }
    assertEquals("<lo><hi>", charEscaper.escape("\uDC00\uD800"));
    try {
      unicodeEscaper.escape("\uDC00\uD800");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass

     * approach would be for each caller CAS it from null to a Set populated with its exception. But
     * there's another race: If the first thread fails with an exception and a second thread
     * immediately fails with the same exception:
     *
     * Thread1: calls setException(), which returns true, context switch before it can CAS
     * seenExceptions to its exception
     *

        assertThrows(RuntimeException.class, () -> service.startAsync().awaitRunning());
    assertThat(e).hasCauseThat().isSameInstanceAs(exception);
    assertEquals(Service.State.FAILED, service.state());
  }

  public void testFunctionalStop_failed() {
    final Exception exception = new Exception("deliberate");
    AbstractIdleService service =
        new DefaultService() {
          @Override