axesSizeProduct[i] = Math.multiplyExact(axesSizeProduct[i + 1], axes.get(i).size());
      }
    } catch (ArithmeticException e) {
      throw new IllegalArgumentException(
          "Cartesian product too large; must have size at most Integer.MAX_VALUE");
    }
    this.axesSizeProduct = axesSizeProduct;
  }

  private int getAxisIndexForProductIndex(int index, int axis) {
    return (index / axesSizeProduct[axis + 1]) % axes.get(axis).size();

 * instance for non-daemon threads.
 *
 * The task runner is also responsible for releasing held threads when the library is unloaded.
 * This is for the benefit of container environments that implement code unloading.
 *
 * Most applications should share a process-wide [TaskRunner] and use queues for per-client work.
 */
class TaskRunner(
  val backend: Backend,
  internal val logger: Logger = TaskRunner.logger,
) : Lockable {

    logger.error("Class not found: " + className, e);
}
```

## 🏗️ Architecture & Design Patterns

### Core Design Principles
CoreLib follows a **utility-class pattern** where most functionality is exposed through static methods:

- **Assertion-based validation** - All methods validate inputs using `AssertionUtil.assertArgumentNotNull()` and `AssertionUtil.assertArgumentNotEmpty()`

      }
    }
  }

  /** Returns the {@code Class} object of arrays with {@code componentType}. */
  static Class<?> getArrayClass(Class<?> componentType) {
    // TODO(user): This is not the most efficient way to handle generic
    // arrays, but is there another way to extract the array class in a
    // non-hacky way (i.e. using String value class names- "[L...")?
    return Array.newInstance(componentType, 0).getClass();

      }
    }
  }

  /** Returns the {@code Class} object of arrays with {@code componentType}. */
  static Class<?> getArrayClass(Class<?> componentType) {
    // TODO(user): This is not the most efficient way to handle generic
    // arrays, but is there another way to extract the array class in a
    // non-hacky way (i.e. using String value class names- "[L...")?
    return Array.newInstance(componentType, 0).getClass();

            .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, postBody))
            .build();

        try (Response response = client.newCall(request).execute()) {
          if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

          System.out.println(response.body().string());
        }
      }
    ```

     *
     * @param fessConfig the Fess configuration
     * @param host       the search engine host address
     * @return the configured HTTP client
     */
    protected Client createHttpClient(final FessConfig fessConfig, final String host) {
        final String[] hosts =
                split(host, ",").get(stream -> stream.map(String::trim).filter(StringUtil::isNotEmpty).toArray(n -> new String[n]));

    checkNotNull(funnel);
    checkArgument(
        expectedInsertions >= 0, "Expected insertions (%s) must be >= 0", expectedInsertions);
    checkArgument(fpp > 0.0, "False positive probability (%s) must be > 0.0", fpp);
    checkArgument(fpp < 1.0, "False positive probability (%s) must be < 1.0", fpp);
    return Collector.of(
        () -> BloomFilter.create(funnel, expectedInsertions, fpp),
        BloomFilter::put,

   */
  open fun onClosed(eventSource: EventSource) {
  }

  /**
   * Invoked when an event source has been closed due to an error reading from or writing to the
   * network. Incoming events may have been lost. No further calls to this listener will be made.
   */
  open fun onFailure(
    eventSource: EventSource,
    t: Throwable?,
    response: Response?,
  ) {
  }

         * TypeVariable implementation. This is a problem because users compare TypeVariables from
         * the JDK against TypeVariables returned by TypeResolver. To work with all JDK versions,
         * TypeResolver must return the appropriate TypeVariable implementation in each of the three
         * possible cases:
         *
         * 1. Under Android, the built-in TypeVariable implementation interoperates with ours.