}

  @Override
  public ImmutableSet<C> columnKeySet() {
    return columnMap().keySet();
  }

  /**
   * {@inheritDoc}
   *
   * <p>The value {@code Map<R, V>} instances in the returned map are {@link ImmutableMap} instances
   * as well.
   */
  @Override
  public abstract ImmutableMap<C, Map<R, V>> columnMap();

  /**
   * {@inheritDoc}
   *

    T getSinkContents() throws IOException;
  }

  /** Factory for {@link ByteSource} instances. */
  interface ByteSourceFactory extends SourceFactory<ByteSource, byte[]> {}

  /** Factory for {@link ByteSink} instances. */
  interface ByteSinkFactory extends SinkFactory<ByteSink, byte[]> {}

  /** Factory for {@link CharSource} instances. */
  interface CharSourceFactory extends SourceFactory<CharSource, String> {}

  }

  @Override
  public ImmutableSet<C> columnKeySet() {
    return columnMap().keySet();
  }

  /**
   * {@inheritDoc}
   *
   * <p>The value {@code Map<R, V>} instances in the returned map are {@link ImmutableMap} instances
   * as well.
   */
  @Override
  public abstract ImmutableMap<C, Map<R, V>> columnMap();

  /**
   * {@inheritDoc}
   *

         *
         * @return The {@link DownloadedArtifact} instance.
         */
        DownloadedArtifact getArtifact();

        /**
         * Returns a mapping of repositories to the exceptions encountered while resolving the artifact.
         *
         * @return A {@link Map} where keys are {@link Repository} instances and values are {@link Exception} instances.
         */

        } catch (final Exception e) {
            logger.warn("Failed to get active instances.", e);
        }
        return instances;
    }

    /**
     * Checks whether the specified instance is currently active.
     *
     * @param targetInstanceId the instance ID to check.
     * @return {@code true} if the instance is active.
     */
    public boolean isInstanceActive(final String targetInstanceId) {

@GwtCompatible
@FunctionalInterface
public interface Supplier<T extends @Nullable Object> extends java.util.function.Supplier<T> {
  /**
   * Retrieves an instance of the appropriate type. The returned object may or may not be a new
   * instance, depending on the implementation.
   *
   * @return an instance of the appropriate type
   */
  @Override
  @ParametricNullness
  T get();

  /**

        // Test that constructor creates a non-null instance
        assertNotNull(crawlerEngineClient);
    }

    // Test inheritance
    @Test
    public void test_inheritance() {
        // Test that CrawlerEngineClient is properly inherited
        assertTrue(crawlerEngineClient instanceof org.codelibs.fess.crawler.client.FesenClient);
    }

    // Test multiple instances
    @Test
    public void test_multipleInstances() {

   * this function.
   *
   * <p><b>Warning: do not depend</b> on the behavior of this method.
   *
   * <p>Historically, {@code Function} instances in this library have implemented this method to
   * recognize certain cases where distinct {@code Function} instances would in fact behave
   * identically. However, as code migrates to {@code java.util.function}, that behavior will
   * disappear. It is best not to depend on it.
   */

/**
 * A factory to create settings builder instances when no dependency injection is available. Note: This class
 * is only meant as a utility for developers that want to employ the settings builder outside of the Maven build system,
 * Maven plugins should always acquire settings builder instances via dependency injection. Developers might want to

    }
  }

  /** Returns a fresh {@link InternerBuilder} instance. */
  public static InternerBuilder newBuilder() {
    return new InternerBuilder();
  }

  /**
   * Returns a new thread-safe interner which retains a strong reference to each instance it has
   * interned, thus preventing these instances from being garbage-collected. If this retention is