if (ext != null)
throw new CacheConfigurationException(String.format(
"Duplicate externalizer id found! Externalizer id=%d for %s is shared by another externalizer (%s)",
id, advancedExternalizer.getClass().getName(), ext.getClass().getName()));
advancedExternalizers.put(id, new LegacyAdvancedExternalizerAdapter(advancedExternalizer));
return this;
}