if (Serializable.class.isAssignableFrom(classToTest)) {
        try {
          Object instance = tester.instantiate(classToTest);
          if (instance != null) {
            if (isEqualsDefined(classToTest)) {
              SerializableTester.reserializeAndAssert(instance);
            } else {
              SerializableTester.reserialize(instance);
            }
          }
        } catch (Throwable e) {

   * `public final Error getCause()`.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *
   * @deprecated Prefer {@linkplain ExecutionError(Error)} a constructor that accepts a cause: Users
   *     of this class typically expect for instances to have a non-null cause. At the moment, you

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

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

    // Test multiple instances
    public void test_multipleInstances() {

@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();

  /**

     * @return this ExecJob instance for method chaining
     */
    public ExecJob timeout(final int timeout) {
        this.timeout = timeout;
        return this;
    }

    /**
     * Sets whether to use local Fesen instance.
     *
     * @param useLocalFesen true to use local Fesen, false otherwise
     * @return this ExecJob instance for method chaining
     */

 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
public interface Supplier<T extends @Nullable Object> {
  /**
   * 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
   */
  @ParametricNullness
  T get();

  /**

  }

  private <T> T pickInstance(T[] instances, T defaultValue) {
    return pickInstance(Arrays.asList(instances), defaultValue);
  }

  private <T> T pickInstance(Collection<T> instances, T defaultValue) {
    if (instances.isEmpty()) {
      return defaultValue;
    }
    // generateInt() is 1-based.
    return Iterables.get(instances, (generateInt() - 1) % instances.size());
  }

                if (!dataCrawlingThreadList.get(i).isRunning() && Constants.RUNNING.equals(dataCrawlingThreadStatusList.get(i))) {
                    dataCrawlingThreadStatusList.set(i, Constants.DONE);
                }
                if (!Constants.DONE.equals(dataCrawlingThreadStatusList.get(i))) {
                    finishedAll = false;
                }
            }

import org.codelibs.fess.Constants;
import org.codelibs.fess.unit.UnitFessTestCase;

public class SystemUtilTest extends UnitFessTestCase {

    public void test_getSearchEngineHttpAddress_null() {
        // Clear the system property to test null case
        String originalValue = System.getProperty(Constants.FESS_SEARCH_ENGINE_HTTP_ADDRESS);
        System.clearProperty(Constants.FESS_SEARCH_ENGINE_HTTP_ADDRESS);

/**
 * Factory interface for creating new RequestCache instances.
 * Implementations should handle the creation and configuration of cache instances
 * based on the current Maven session and environment.
 *
 * @since 4.0.0
 * @see RequestCache
 */
@Experimental
public interface RequestCacheFactory {

    /**
     * Creates a new RequestCache instance.