Comparative Analysis of Spring Boot and Quarkus for Cloud‑Native Java Applications

Spring Boot is a well‑known Java framework for enterprise applications, while Quarkus is a newer Kubernetes‑native Java framework marketed as “Supersonic Subatomic Java”. This article provides a concise comparison of the two frameworks, presents performance test results, and discusses migration from Spring Boot to Quarkus.

Overview

Both frameworks support the same Java ecosystem, but Quarkus is specifically optimized for OpenJDK HotSpot, GraalVM, and containerized environments. It promises faster startup, lower memory usage, and the ability to produce native images.

Test Application

A reactive sample application implements three APIs (create, lookup, and city‑wise query of postal codes) using Spring WebFlux and Quarkus reactive extensions, with PostgreSQL as the backing store.

Test Plan

JMeter is used to generate load for 5 minutes, gradually increasing concurrent users up to 1,500. VisualVM monitors CPU, memory, and thread usage. All tests run on a single‑machine specification (details shown in the original figures).

Investigation Results

Quarkus consistently outperforms Spring Boot in startup time and build time. Native image build times are 9 min (Quarkus) vs 13 min (Spring Boot); JVM build times are 20 s vs 39 s. Artifact sizes are also smaller (75 MB vs 109 MB for native, 4 KB vs 26 MB for JVM).

CPU usage during the warm‑up phase is higher for Spring Boot, but stabilizes across both frameworks. Memory consumption is lower for Quarkus, especially in native mode, though native images show higher peak usage during the test.

Response time and thread count favor Spring Boot slightly, with the JVM version achieving the best latency due to JIT optimizations. Overall, both frameworks handle the workload without errors and show comparable throughput.

Migration Considerations

Quarkus offers Spring API compatibility (DI, Web, Data JPA) and can compile many Spring‑based libraries to native binaries. Benefits for Spring developers include:

FaaS readiness – native binaries start in ~0.0015 s.

Live coding – changes are reflected instantly without restarts.

Support for both reactive and imperative models.

Compile‑time detection of DI errors.

Combination of best‑of‑breed frameworks and standards (Spring, Vert.x, MicroProfile, etc.).

Getting Started for Spring Developers

Recommended steps: read the Quarkus introductory guide, explore Spring‑specific extensions (DI, Web, Data JPA), and generate a new project via code.quarkus.io .

Code Examples

import java.util.List;
import java.util.Optional;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/person")
public class PersonController {
    @GetMapping(path = "/greet/{id}", produces = "text/plain")
    public String greetPerson(@PathVariable(name = "id") long id) {
        String name = "";
        // ...
        return name;
    }

    @GetMapping(produces = "application/json")
    public Iterable
findAll() {
        return personRepository.findAll();
    }
}

package org.acme.springmp;

import java.util.List;
import org.springframework.data.repository.CrudRepository;

public interface PersonRepository extends CrudRepository
{
    List
findByAge(int age);
}

import org.eclipse.microprofile.faulttolerance.Fallback;
import org.eclipse.microprofile.faulttolerance.Timeout;
import org.eclipse.microprofile.rest.client.inject.RestClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
public class PersonService {
    @Autowired
    @RestClient
    SalutationMicroProfileRestClient salutationRestClient;

    @Value("${fallbackSalutation}")
    String fallbackSalutation;

    @CircuitBreaker(delay=5000, failureRatio=.5)
    @Fallback(fallbackMethod = "salutationFallback")
    public String getSalutation() {
        return salutationRestClient.getSalutation();
    }
}