Inhttp://symfony.com/doc/current/cookbook/debugging.html#disabling-the-bootstrap-file-and-class-caching say that you can disable the generation of the class cache by removing the call to theloadClassCache() method from theKernel class. However, this is no longer true with the newClassCacheCacheWarmer that was introduced in Symfony 2.8 and generates the class cache when the application cache is warmed up (see alsosymfony/symfony#17439).