Tables with engines of "MEMORY" does not get dropped when server is restarted

I read a description from When to Use MEMORY or NDB Cluster from the MySQL website. > Operations involving transient, non-critical data such as session > management or caching. When the MySQL server halts or restarts, the > data in MEMORY tables is lost. but my created tables with ENGINES = MEMORY were not dropped upon mysql server restart. CREATE TABLE MY_TEMPORARY_TABLE ( COLUMN_1 varchar(255) DEFAULT NULL, COLUMN_2 varchar(255) DEFAULT NULL, COLUMN_3 varchar(255) DEFAULT NULL ) ENGINE=MEMORY DEFAULT CHARSET=utf8;