What does "Liskov Substitution Principle" mean in programming?
Liskov Substitution Principle is one of the most common terms in software development. This guide explains what it means, how it is used in practice, and why it matters, with real examples from the developer world.
Definition
The L in SOLID. Objects of a subclass should be replaceable with objects of the parent class without breaking the program. If a subclass overrides a method in a way that changes its expected behavior, it violates LSP. The classic example: a Penguin subclass of Bird that throws an error from fly().
Example
"Our Square class extends Rectangle but breaks LSP: setting width also changes height, which callers of Rectangle do not expect."
Related terms
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