SpecificationCacheDefault { public T get(String className) { return specByClassName.get(className); }  T get(String className); T computeIfAbsent(
            String className, 
            Function<? super String, T> mappingFunction); void clear(); Collection<T> snapshotSpecs(); Class<?> resolveType(final ObjectSpecId objectSpecID); T getByObjectType(final ObjectSpecId objectSpecID); T remove(String typeName); void recache(T spec);  }
@Test public void get_whenNotCached() { assertNull(specificationCache.get(Customer.class.getName())); }