Pros of Graal

• Offers advanced JIT compilation and ahead-of-time compilation capabilities
• Supports multiple programming languages through Truffle framework
• Provides significant performance improvements for Java applications

Cons of Graal

• Steeper learning curve and more complex setup compared to Helidon
• May have compatibility issues with some existing Java libraries
• Requires more resources for development and deployment

Code Comparison

Helidon (Reactive WebServer):

Routing.builder()
    .get("/greet", (req, res) -> res.send("Hello World!"))
    .build();
WebServer.create(routing).start();

Graal (Native Image):

@CEntryPoint(name = "main")
static void main(IsolateThread thread, int argc, CCharPointer argv) {
    System.out.println("Hello World!");
}

Summary

Graal is a high-performance JVM and JIT compiler with polyglot capabilities, while Helidon is a lightweight microservices framework. Graal excels in performance optimization and language support, but has a steeper learning curve. Helidon offers simpler development for microservices but may not provide the same level of performance optimization. The choice between them depends on project requirements, performance needs, and development team expertise.

Pros of Micronaut

• Faster startup time and lower memory footprint due to compile-time dependency injection
• Extensive support for cloud-native features and microservices architecture
• Rich ecosystem with numerous modules and integrations

Cons of Micronaut

• Steeper learning curve, especially for developers new to AOT compilation concepts
• Less mature compared to Helidon, which is backed by Oracle

Code Comparison

Micronaut:

@Controller("/hello")
public class HelloController {
    @Get("/{name}")
    public String hello(String name) {
        return "Hello, " + name + "!";
    }
}

Helidon:

@Path("/hello")
public class HelloResource {
    @GET
    @Path("/{name}")
    public String hello(@PathParam("name") String name) {
        return "Hello, " + name + "!";
    }
}

Both frameworks offer similar syntax for creating RESTful endpoints, but Micronaut uses its own annotations while Helidon leverages JAX-RS annotations. Micronaut's approach aligns with its focus on compile-time processing, while Helidon's use of standard Java EE annotations may be more familiar to some developers.

Pros of Quarkus

• Faster startup time and lower memory footprint due to its container-first approach
• Extensive support for GraalVM native compilation, enhancing performance
• Broader ecosystem with more extensions and integrations available

Cons of Quarkus

• Steeper learning curve, especially for developers new to reactive programming
• Less flexibility in terms of customization compared to Helidon's modular approach
• Larger community and more frequent updates may lead to faster deprecation of features

Code Comparison

Helidon:

@Path("/hello")
public class HelloResource {
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String hello() {
        return "Hello, World!";
    }
}

Quarkus:

@Path("/hello")
public class HelloResource {
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String hello() {
        return "Hello, World!";
    }
}

In this basic example, both frameworks use similar JAX-RS annotations for creating RESTful endpoints. However, Quarkus often requires less boilerplate code for more complex scenarios and offers additional features like live coding and unified configuration.

Pros of Spring Boot

• Extensive ecosystem with a wide range of starter dependencies
• Large and active community, providing robust support and resources
• Mature framework with proven track record in enterprise applications

Cons of Spring Boot

• Can be heavyweight for smaller applications or microservices
• Steeper learning curve for beginners due to its comprehensive feature set

Code Comparison

Spring Boot:

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Helidon:

public class Main {
    public static void main(String[] args) {
        Server server = Server.create().start();
        System.out.println("Server started at: http://localhost:" + server.port());
    }
}

Spring Boot offers a more opinionated and convention-based approach, while Helidon provides a lightweight and flexible foundation for building microservices. Spring Boot's annotations and auto-configuration simplify development, whereas Helidon's approach gives developers more control over the application structure.

Both frameworks support reactive programming and microservices architecture, but Spring Boot's extensive ecosystem and mature tooling give it an edge for larger, more complex applications. Helidon, being lighter and more focused on microservices, may be preferable for smaller, more targeted projects or when working within the Oracle ecosystem.

Pros of Vert.x

• More mature and established project with a larger community
• Highly flexible and modular architecture
• Supports multiple programming languages (polyglot)

Cons of Vert.x

• Steeper learning curve due to its flexibility
• Less opinionated, requiring more configuration and setup

Code Comparison

Vert.x:

Vertx vertx = Vertx.vertx();
vertx.createHttpServer().requestHandler(req -> {
  req.response().end("Hello from Vert.x!");
}).listen(8080);

Helidon:

WebServer.create(Routing.builder()
    .get("/", (req, res) -> res.send("Hello from Helidon!"))
    .build())
    .start();

Both frameworks offer reactive programming models, but Vert.x provides a more low-level API, giving developers more control over the application's behavior. Helidon, on the other hand, offers a more streamlined approach with built-in support for microservices architecture and configuration management.

Vert.x excels in scenarios requiring high concurrency and scalability, while Helidon is better suited for rapid development of cloud-native microservices, especially when working within the Oracle ecosystem.