1 of 14

UNIT - 3

Web Sites for Non-Browsers: JAX-RS

Building RESTful Services for Programmatic Clients

https://ravulakartheek.blogspot.com/

2 of 14

Introduction

Not all clients are web browsers
Applications, scripts, IoT devices, and mobile apps often need machine-readable data
JAX-RS provides a standard for building RESTful APIs in Java
Purpose: Show how to design “web sites for non-browsers” using JAX-RS

https://ravulakartheek.blogspot.com/

3 of 14

What Is JAX-RS?

Java API for RESTful Web Services
Part of the Jakarta EE ecosystem
Uses annotations to simplify development
Provides automatic content negotiation (JSON, XML, etc.)

https://ravulakartheek.blogspot.com/

4 of 14

Why Non-Browser Clients?

Integration with external systems
Mobile and desktop apps
Microservices communication
Automated processes (cron jobs, data pipelines)
IoT devices consuming REST endpoints

https://ravulakartheek.blogspot.com/

5 of 14

REST vs. Traditional Web Pages

Traditional Web	RESTful Service
HTML pages	JSON/XML data
Designed for browsers	Designed for apps
UI-driven	API-driven
Sessions	Stateless

https://ravulakartheek.blogspot.com/

6 of 14

Core JAX-RS Annotations

@Path – define resource routes
@GET, @POST, @PUT, @DELETE – HTTP method handlers
@Produces – define output format
@Consumes – define expected input format
@PathParam, @QueryParam, @HeaderParam – parameter injection

https://ravulakartheek.blogspot.com/

7 of 14

Example REST Resource

@Path("/hello")

public class HelloResource {

@GET

@Produces(MediaType.APPLICATION_JSON)

public Map<String, String> hello() {

return Map.of("message", "Hello, Non-Browser Client!");

}

Clients receive JSON data
Ideal for apps, scripts, and devices

https://ravulakartheek.blogspot.com/

8 of 14

Content Negotiation

JAX-RS supports automatic selection via HTTP headers:
Client example:
Accept: application/json
Accept: application/xml

Server decides the best match based on:

@Produces
Client header preferences

https://ravulakartheek.blogspot.com/

9 of 14

Returning JSON

Most common format for non-browser apps.

@GET

@Produces(MediaType.APPLICATION_JSON)

public User getUser() {

return new User("Alice", 25);

}

https://ravulakartheek.blogspot.com/

10 of 14

Handling Parameters

Path parameters:

@GET

@Path("/{id}")

public User getUser(@PathParam("id") int id) { ... }

Query parameters:

@GET

public List<User> search(@QueryParam("name") String name) { ... }

https://ravulakartheek.blogspot.com/

11 of 14

POST Example (Create Resource)

@POST

@Consumes(MediaType.APPLICATION_JSON)

public Response createUser(User user) {

service.save(user);

return Response.status(201).build();

}

https://ravulakartheek.blogspot.com/

12 of 14

Tools for Testing Non-Browser APIs

curl / httpie
Postman
Insomnia
Mobile apps
Shell scripts
Python scripts
IoT devices (ESP32, Raspberry Pi, etc.)

https://ravulakartheek.blogspot.com/

13 of 14

Best Practices

Use proper HTTP status codes

Validate input

Provide consistent JSON structures

Implement error handling

Document with OpenAPI/Swagger

Secure endpoints (JWT, OAuth2, API keys)

https://ravulakartheek.blogspot.com/

14 of 14

Summary

Non-browser clients rely on machine-readable APIs

JAX-RS provides a clean, annotation-based approach to REST

Supports JSON, XML, and content negotiation

Ideal for mobile, IoT, and server integrations

https://ravulakartheek.blogspot.com/