* pendingToString().)
       */
      CombinedFuture.this.task = null;

      setValue(result);
    }

    @Override
    final void afterRanInterruptiblyFailure(Throwable error) {
      // See afterRanInterruptiblySuccess.
      CombinedFuture.this.task = null;

      if (error instanceof ExecutionException) {
        /*

        verify(mockContext).withCredentials(creds);
    }

    @Test
    @DisplayName("Should renew credentials")
    void testRenewCredentials() {
        // Given
        String hint = "hint";
        Throwable error = new Exception();
        when(mockContext.renewCredentials(hint, error)).thenReturn(true);

        // When
        boolean renewed = mockContext.renewCredentials(hint, error);

        // Then

      notifyStopped();
    }
  }

  /** This is never thrown but only used for logging. */
  private static final class EmptyServiceManagerWarning extends Throwable {}

  private static final class FailedService extends Throwable {
    FailedService(Service service) {
      super(
          service.toString(),
          service.failureCause(),
          false /* don't enable suppression */,

            events.add(new LogNotificationEvent(((Number) source.get("timestamp")).longValue(), (String) source.get("level"),
                    (String) source.get("loggerName"), (String) source.get("message"), (String) source.get("throwable")));
            docIds.add(hit.getId());
        }

        final int maxDetailsLength = fessConfig.getLogNotificationMaxDetailsLengthAsInteger();

        assertTrue(exception instanceof FessSystemException);
        assertTrue(exception instanceof RuntimeException);
        assertTrue(exception instanceof Exception);
        assertTrue(exception instanceof Throwable);
    }

    @Test
    public void test_serializable() {
        // Test that the exception has serialVersionUID
        WebApiException exception = new WebApiException(404, "Not Found");

                 * to return a proper ListenableFuture instead of using listenInPoolThread.
                 */
                getUninterruptibly(delegate);
              } catch (Throwable t) {
                // (including CancellationException and sneaky checked exception)
                // The task is presumably done, run the listeners.

            } else if (logger.isInfoEnabled()) {
                logger.info("ThumbnailGenerator is stopped.");
            }
            exitCode = Constants.EXIT_FAIL;
        } catch (final Throwable t) {
            logger.error("ThumbnailGenerator terminated unexpectedly.", t);
            exitCode = Constants.EXIT_FAIL;
        } finally {
            if (systemMonitorTask != null) {

```

**Async Operations:**
```java
suggester.suggest()
    .setQuery("search")
    .execute()
    .done(response -> { /* handle success */ })
    .error(throwable -> { /* handle error */ });
```

---

## Important Notes

### Thread Safety
- **Suggester**: Thread-safe for queries
- **SuggestIndexer**: Thread-safe for indexing

        /**
         * Create exception with cause
         *
         * @param message error message
         * @param cause underlying cause
         */
        public NoAvailableChannelException(String message, Throwable cause) {
            super(message, cause);
        }
    }

        assertNotNull(details);
        assertTrue(details.contains("Total: 1 event(s)"));
        assertTrue(details.contains("Something went wrong"));
        // Throwable is no longer included in summary-oriented format
        // Only log message is shown per event line
    }

    @Test
    public void test_formatDetails_emptyList() {