Covariance and Contravariance

The intuition behind Covariance and Contravariance explained with 🍎, oranges 🍊, and cats 🐈. 💚 BUY MY BOOK: https://leanpub.com/the-object-oriented-way/ 00:00 Question 00:41 Fruit example (Covariance) 01:14 Fruit example (Contravariance) 02:03 UML (Covariance) 03:24 UML (Contravariance) 04:53 Formal definitions 06:12 Type safety 07:16 Robustness Principle 08:20 Invariant list (Covariance) 09:43 Invariant list (Contravariance) 10:59 Invariant list (summary) 11:44 Where to use variance 12:57 Summary (Reuploaded because of a mistake in the original upload)