### Question:
App { public static void main(String[] args) { var ivoryTower1 = IvoryTower.getInstance(); var ivoryTower2 = IvoryTower.getInstance(); LOGGER.info("ivoryTower1={}", ivoryTower1); LOGGER.info("ivoryTower2={}", ivoryTower2); var threadSafeIvoryTower1 = ThreadSafeLazyLoadedIvoryTower.getInstance(); var threadSafeIvoryTower2 = ThreadSafeLazyLoadedIvoryTower.getInstance(); LOGGER.info("threadSafeIvoryTower1={}", threadSafeIvoryTower1); LOGGER.info("threadSafeIvoryTower2={}", threadSafeIvoryTower2); var enumIvoryTower1 = EnumIvoryTower.INSTANCE; var enumIvoryTower2 = EnumIvoryTower.INSTANCE; LOGGER.info("enumIvoryTower1={}", enumIvoryTower1); LOGGER.info("enumIvoryTower2={}", enumIvoryTower2); var dcl1 = ThreadSafeDoubleCheckLocking.getInstance(); LOGGER.info(dcl1.toString()); var dcl2 = ThreadSafeDoubleCheckLocking.getInstance(); LOGGER.info(dcl2.toString()); var demandHolderIdiom = InitializingOnDemandHolderIdiom.getInstance(); LOGGER.info(demandHolderIdiom.toString()); var demandHolderIdiom2 = InitializingOnDemandHolderIdiom.getInstance(); LOGGER.info(demandHolderIdiom2.toString()); }  static void main(String[] args);  }### Answer:
@Test void shouldExecuteWithoutException() { assertDoesNotThrow(() -> App.main(new String[]{})); }