public T getOrDefaultExtension(String name) {
        return containsExtension(name) ? getExtension(name) : getDefaultExtension();
    }
@Test
    void testGetOrDefaultExtension() {
        ExtensionLoader<InjectExt> loader = getExtensionLoader(InjectExt.class);
        InjectExt injectExt = loader.getOrDefaultExtension("non-exists");
        assertEquals(InjectExtImpl.class, injectExt.getClass());
        assertEquals(
                InjectExtImpl.class, loader.getOrDefaultExtension("injection").getClass());
    }