First of all, Liskov was a woman, okay? That being said, let’s continue; In object-oriented programming, classes are user-defined data structures that group related attributes and methods, allowing developers to model real-world objects or abstract ideas.
These classes can relate to one another through inheritance, a key concept that lets subclasses acquire its properties and behaviors.
Inheritance promotes code reuse and specialization, but it must be used carefully. The Liskov Substitution Principle (LSP) provides guidance: if a subclass is a subtype of a base class, it should be able to replace it without altering the program’s behavior.
To satisfy the LSP, subclasses must not change the meaning of methods, weaken postconditions, or modify immutable attributes from the base class. They can, however, extend functionality or improve performance, as long as the expected results remain consistent.
In short, inheritance should maintain consistency between base and derived classes, ensuring that substituting one for the other keeps the system stable and predictable.