### Question:
InternalLoggerFactory { public static void setDefaultFactory(InternalLoggerFactory defaultFactory) { if (defaultFactory == null) { throw new NullPointerException("defaultFactory"); } InternalLoggerFactory.defaultFactory = defaultFactory; }  static InternalLoggerFactory getDefaultFactory(); static void setDefaultFactory(InternalLoggerFactory defaultFactory); static InternalLogger getInstance(Class<?> clazz); static InternalLogger getInstance(String name);  }### Answer:
@Test(expected = NullPointerException.class) public void shouldNotAllowNullDefaultFactory() { InternalLoggerFactory.setDefaultFactory(null); }