However, the first call to codice_1 will create the object and only the few threads trying to access it during that time need to be synchronized; after that all calls just get a reference to the member variable.
Первый вызов codice_1 создаст объект, и нужно синхронизировать только те несколько потоков, которые будут вызывать codice_1 во время инициализации объекта.