JsonElement elt = packer.pack(entity);
elt.getAsJsonObject().get("value").getAsJsonObject().addProperty("@", "UnknownType");
Annotation a = unpacker.<Annotation> unpack(Annotation.class, elt, null).getValue();
assertTrue(a instanceof UnknownAnnotation);
AnnotationInfo info = (AnnotationInfo) a;
assertEquals("UnknownType", info.getAnnotationTypeName());
assertEquals(5, ((Number) info.getAnnotationValues().get("i")).intValue());
}