Inheritance vs Composition
What you’ll learn: Why Rust favors composition over class inheritance and how Java design patterns change under that pressure.
Difficulty: 🟡 Intermediate
Rust has no class inheritance. That is not a missing feature by accident; it is a design decision.
What Replaces Inheritance
- traits for shared behavior
- structs for data ownership
- delegation for reuse
- enums for explicit variant modeling
Why This Helps
Inheritance-heavy code often mixes state sharing, behavioral polymorphism, and framework convenience into one mechanism. Rust separates those concerns, which can make designs flatter and easier to audit.
Advice for Java Developers
- model behavior with traits
- reuse implementation through helper types and delegation
- use enums where inheritance trees only exist to model variants
Composition in Rust is usually less magical and more honest about where behavior really lives.