* @param instance the component instance
         * @param initializer the initializer function (can be null)
         * @param container the container instance for dependency injection
         */
        protected ComponentDef(final T instance, final Consumer<T> initializer, final StandardCrawlerContainer container) {
            this.instance = instance;
            this.initializer = initializer;

    void testGetInstanceWithoutSetInstance() {
        // Test getInstance when no instance has been set
        // Should default to System.err
        LogStream instance = LogStream.getInstance();
        assertNotNull(instance);

        // Getting instance again should return the same instance
        LogStream instance2 = LogStream.getInstance();
        assertSame(instance, instance2);
    }

    @Test

    // Use reflection to reset the singleton instance between tests
    @BeforeEach
    @AfterEach
    void resetSingleton() {
        try {
            Field instance = SingletonContext.class.getDeclaredField("INSTANCE");
            instance.setAccessible(true);
            instance.set(null, null);
        } catch (NoSuchFieldException | IllegalAccessException e) {

        byte[] buffer = new byte[] { (byte) 0xff, (byte) 0xff, 0, 0, 0, 0, 0, 0 };
        SmbComWriteAndXResponse instance = new SmbComWriteAndXResponse(config);

        // When
        int result = instance.readParameterWordsWireFormat(buffer, 0);

        // Then
        assertEquals(8, result);
        assertEquals(0xffffL, instance.getCount());
    }

    /**
     * Test of readParameterWordsWireFormat with zero count
     */

         * @param status The status to set.
         * @return This ApiResponse instance.
         */
        public ApiResponse status(final Status status) {
            this.status = status.getId();
            return this;
        }

        /**
         * Returns a new ApiResult instance with this ApiResponse.
         * @return A new ApiResult instance.
         */
        public ApiResult result() {

But we want to be able to parameterize that fixed content.

## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[12] *}

      @ParametricNullness T instance) {
    return new SupplierOfInstance<>(instance);
  }

  private static final class SupplierOfInstance<T extends @Nullable Object>
      implements Supplier<T>, Serializable {
    @ParametricNullness final T instance;

    SupplierOfInstance(@ParametricNullness T instance) {
      this.instance = instance;
    }

    @Override
    @ParametricNullness
    public T get() {

     * <p>
     * If a root package is specified at instance construction, the specified class name is interpreted as a relative name from the root package.
     * </p>
     *
     * @param className the class name
     * @return <code>true</code> if the class file exists in the resources handled by this instance
     */
    boolean isExistClass(final String className);

      for (Invokable<?, ?> factory : getFactoriesToTest()) {
        Object instance = instantiate(factory);
        if (instance != null
            && packagesToTest.contains(Reflection.getPackageName(instance.getClass()))) {
          try {
            nullPointerTester.testAllPublicInstanceMethods(instance);
          } catch (AssertionError e) {

	<component name="crawler" class="org.codelibs.fess.crawler.Crawler" instance="prototype" >
	</component>

	<!-- Crawler Thread -->
	<component name="crawlerThread" class="org.codelibs.fess.crawler.CrawlerThread" instance="prototype" >
	</component>

	<!-- Entity -->
	<component name="accessResult" class="org.codelibs.fess.crawler.entity.AccessResultImpl" instance="prototype" >
	</component>