protected StoresImpl<K,E> _constructStores(SharedServiceStuff stuff)
throws IOException
{
final SCONFIG v = stuff.getServiceConfig();
StoreBackendBuilder<?> b = v.instantiateBackendBuilder();
StoreBackendConfig backendConfig = v._storeBackendConfigOverride;
if (backendConfig == null) { // no overrides, use databinding
Class<? extends StoreBackendConfig> cfgType = b.getConfigClass();
if (v.storeBackendConfig == null) {
throw new IllegalStateException("Missing 'v.storeBackendConfig");
}