### Question:
FactoryUtils { public static <T> Factory<T> nullFactory() { return ConstantFactory.<T>constantFactory(null); } private  FactoryUtils(); static Factory<T> exceptionFactory(); static Factory<T> nullFactory(); static Factory<T> constantFactory(final T constantToReturn); static Factory<T> prototypeFactory(final T prototype); static Factory<T> instantiateFactory(final Class<T> classToInstantiate); static Factory<T> instantiateFactory(final Class<T> classToInstantiate, final Class<?>[] paramTypes,
                                                    final Object[] args);  }### Answer:
@Test public void testNullFactory() { final Factory<Object> factory = FactoryUtils.nullFactory(); assertNotNull(factory); final Object created = factory.create(); assertNull(created); }