rust-for-java-developers.md

Rust for Java Developers

This guide is for Java, Spring Boot, and backend developers learning Rust.

Java developers already understand many useful ideas:

• types
• interfaces
• backend services
• HTTP APIs
• databases
• dependency management
• production systems

But Rust uses a different mental model.

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Java vs Rust

Concept	Java	Rust
Memory	Garbage collector	Ownership
Classes	Central	No traditional classes
Interfaces	Interfaces	Traits
Exceptions	try/catch	Result<T, E>
Null	null	Option
Build tool	Maven/Gradle	Cargo
Web framework	Spring Boot	Axum / Actix Web
ORM	Hibernate/JPA	SQLx / Diesel
Concurrency	Threads/executors	Tokio + async/await

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What Java Developers Must Unlearn

In Java, you often rely on:

• garbage collection
• inheritance
• runtime exceptions
• null
• framework magic
• annotations
• dependency injection containers

Rust is more explicit.

Rust prefers:

• ownership
• composition
• traits
• explicit error handling
• Option instead of null
• small libraries instead of heavy frameworks

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Rust Traits vs Java Interfaces

Java:

interface PaymentProcessor {
    void pay();
}