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oopdesign-patternssolid-principlesliskov-substitution-principle

Liskov vs Override

Liskov says : you can't change the super class behaviors in child class.
Override says : you can change the super class behavior in child class.

I am confuse and i don't realize which one is correct?

Thank you for answers

Solution

  • Overriding is a technology. The Liskov Substitution Principle is a rule about how to use that technology. Many programming languages say you can override a method in a child-class, but Barbara Liskov says that you probably shouldn't in most cases.

    Keep in mind that the Lisokv Substitution Principle does not say that you must never use override. You just should not use it in a way which causes code intended to work with your base class to not work anymore if it has to work with your child class instead. So if you override a method, you need to ensure that your override still fulfills the contract of the original method.