I knew the definitions fine but fumbled a bit when they asked me to show polymorphism in the code itself, not just write a subclass.
Start by clearly defining inheritance as a mechanism for code reuse and establishing an 'is-a' relationship, and polymorphism as the ability of different types to respond to the same interface. Then, provide a concise code example that demonstrates method overriding and dynamic dispatch, explaining how the child class's method is called at runtime based on the actual object type.
Pro tip: Emphasize that polymorphism enables extensibility and decoupling, which are crucial for scalable systems like those at Amazon. Mention that while inheritance is one way to achieve polymorphism, composition and interfaces often provide more flexible designs.
Explain that inheritance allows a child class to acquire properties and methods from a parent class, promoting code reuse and hierarchical classification.
Describe polymorphism as the ability of objects of different classes to be treated as objects of a common superclass, with method calls resolved at runtime (dynamic dispatch).
Highlight that inheritance is about reusing and extending behavior, while polymorphism is about flexibility in invoking behavior, often enabled by inheritance but also achievable via interfaces.
Write a simple code snippet (e.g., in Java or Python) with a parent class and a child class that overrides a method, then show a polymorphic call using a parent reference to a child object.
Walk through the code to show that the child's overridden method is invoked, demonstrating dynamic dispatch and the practical impact of polymorphism.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.