Liskov Substitution Principle in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Liskov Substitution Principle (LSP)?

LSP means that objects of a parent class should be replaceable with objects of a child class without changing the correctness of the program.

beginner

Why is LSP important in system design?

It ensures that components can be replaced or extended without breaking the system, making designs more flexible and maintainable.

beginner

Give a simple real-life example of LSP.

If a car can be replaced by an electric car without changing how you drive it, then the electric car follows LSP with car.

intermediate

What can happen if LSP is violated?

Replacing a parent object with a child object may cause errors or unexpected behavior, breaking the system.

intermediate

How does LSP relate to method overriding?

Overridden methods in child classes must behave consistently with the parent methods to follow LSP.

What does the Liskov Substitution Principle ensure?

A Child classes can replace parent classes without errors

B Parent classes cannot be extended

C Child classes must have fewer methods

D Parent classes must be abstract

LSP ensures child classes can replace parent classes without breaking the program.

Which of these violates LSP?

A Child class adds new methods

B Child class changes method behavior breaking parent expectations

C Child class inherits all parent methods unchanged

D Parent class is abstract

Changing method behavior that breaks parent expectations violates LSP.

LSP is a principle related to which programming concept?

A Network protocols

B Database normalization

C Inheritance and polymorphism

D UI design

LSP deals with inheritance and polymorphism in object-oriented programming.

If a subclass method throws unexpected exceptions not declared in the parent, does it follow LSP?

A No, it violates LSP

B Yes, it follows LSP

C Only if exceptions are caught

D Exceptions do not affect LSP

Throwing unexpected exceptions breaks the contract and violates LSP.

Which is a benefit of following LSP in system design?

A Less reusable code

B More complex code

C Slower performance

D Easier to extend and maintain code

Following LSP makes code easier to extend and maintain.

Explain the Liskov Substitution Principle with a simple example.

Think about replacing a parent object with a child object without breaking the system.

Describe what can go wrong if the Liskov Substitution Principle is not followed in a system.

Consider what happens when a child class does not behave like its parent.