ADR-0001-use-restclient.md

ADR-0001: Use RestClient Instead of RestTemplate

Status: Accepted Date: 2025-12-13

Context

The original Spring guide "Consuming a RESTful Web Service" uses RestTemplate to call the quote service. However, RestClient was introduced in Spring Boot 3.2 as the modern alternative for synchronous HTTP calls and is fully supported in Spring Boot 4.0.0 (which this project uses).

We need to decide which HTTP client to use for this tutorial.

Decision

Use RestClient instead of RestTemplate.

RestClient is the recommended approach for synchronous REST calls in Spring Boot 4.x. RestTemplate is now in maintenance mode and will not receive new features.

Key advantages of RestClient:

• Fluent API similar to WebClient
• Auto-configured RestClient.Builder provided by Spring Boot
• Better ergonomics than RestTemplate
• Actively maintained (RestTemplate is not)

Consequences

Easier:

• Cleaner, more readable code with fluent API
• Aligns with current Spring Boot best practices
• Better prepared for future Spring versions

Harder:

• Code differs from the original Spring guide (which uses RestTemplate)

References

• https://docs.spring.io/spring-boot/reference/io/rest-client.html
• https://docs.spring.io/spring-framework/reference/integration/rest-clients.html
• https://www.baeldung.com/spring-boot-restclient