Must-do problems: Abstraction and Interfaces

120 min · Beginner

Back to syllabus (Abstraction & Interfaces)

Every problem here is a small design: decide what is the contract, what is shared code in an abstract parent, and what each class writes for itself. Write the types first, keep main working only through the contract, and run every test before opening a hint.

What you will learn

Choose an abstract class for a family and an interface for an ability
Write template methods that call abstract steps
Use default, static and clashing default methods in interfaces
Pass small rules as lambdas of a functional interface

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