Why a Veteran Java Developer Chose Rust: Performance, Concurrency, and Ecosystem

Rust (The Rust Language)

The author, a Java developer with ten years of experience, reflects on why he decided to explore Rust as an alternative for building command‑line tools, libraries, and network applications, citing several technical advantages.

Ideal for Command‑Line Tools (CLI)

Java’s large runtime footprint makes it unsuitable for small, fast CLI utilities. Rust produces tiny binaries (well under 60 MB) that start instantly and run efficiently.

Better Resource Utilization

A proof‑of‑concept conversion of a simple application to Rust showed dramatic improvements. Under a four‑times‑load test, the Rust version used less than 8 MB of memory compared with 850 MB for the Java version, and consumed only 11 ms of CPU time versus 161 ms for Java.

Easy Concurrency

Rust’s type system and ownership model make concurrent programming safer and more straightforward. Shared memory can be handled with Arc and Mutex, and the compiler enforces correct usage, eliminating many of the pitfalls present in Java’s synchronized blocks and lock objects.

Built‑in Asynchronous Programming

Rust includes native async/await syntax. The Tokio runtime is the de‑facto standard for async execution, while Actix‑web is a popular, high‑performance web framework designed around async.

Why Java Still Exists

Despite claims that Java is obsolete, it remains one of the most popular languages for business applications due to several factors.

Ease of Learning and Understanding

Java’s simple type system and extensive documentation allow developers to become productive quickly, facilitating rapid feature deployment and easy code modifications.

The author lists three primary concerns when evaluating a language for business work:

Speed of deploying new features.

Ease of modifying existing code.

Performance.

He prioritises the first two, as they directly impact customer satisfaction and business value.

Ecosystem and Libraries

Java’s Maven repository hosts over 11 million libraries, with mature, battle‑tested components such as Spring Boot, Spring Data, and Spring Security that enable rapid microservice development through auto‑configuration and convention‑over‑configuration.

Rust’s ecosystem is growing, with around 118 000 crates. While some, like actix‑web and rdkafka, provide powerful functionality, they often require more initial effort, manual configuration, or additional wrappers to match Java’s out‑of‑the‑box experience.

Are These Concerns Real Deal‑Breakers?

When building a new service, many of the perceived drawbacks of Rust are mitigated by focusing on business logic rather than low‑level plumbing. Developers can create higher‑level wrappers around low‑level crates (e.g., a friendly Kafka wrapper) to simplify usage, similar to what Spring Boot offers for Java.

The author concludes that, although Rust presents a steeper learning curve—especially around ownership, the borrow checker, and lifetimes—its performance, safety, and modern tooling make it an attractive choice for future projects. He plans to transition to full‑time Rust development, while affirming that Java is far from dead.