This is how my connection is set:
Connection conn = DriverManager.getConnection(url + dbName + \"?useUnicode=true&characterEncoding=utf-8\", userName, password
The strings that contain \xF0
are simply characters encoded as multiple bytes using UTF-8.
Although your collation is set to utf8_general_ci, I suspect that the character encoding of the database, table or even column may be different. They are independent settings. Try:
ALTER TABLE database.table MODIFY COLUMN col VARCHAR(255)
CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;
Substitute whatever your actual data type is for VARCHAR(255)