Hands-on Examples on Advanced Beginner

Environment Setup

d8lzz1gpw@mozmail.com (kimbenji) — Sat, 10 Jan 2026 00:00:00 +0000

Reference guide for setting up Kafka with Spring Boot.

TL;DR

Kafka Execution: Run Kafka 3.6.1 in KRaft mode via Docker Compose

Dependencies: Add spring-kafka, spring-boot-starter-web

Basic Settings: Configure bootstrap-servers, Serializer/Deserializer, group-id

Production: Ensure stability with acks: all, enable.idempotence: true

Target Audience and Prerequisites#

Item	Description
Target Audience	Developers setting up Kafka environment in Spring Boot projects
Prerequisites	Basic Docker usage, Gradle or Maven build tools, Spring Boot configuration files (application.yml)
Required Tools	Docker Desktop or Docker Engine, JDK 17+, IDE (IntelliJ IDEA recommended)
Estimated Time	About 15 minutes

If you completed Quick Start, you’ve already set up the basic environment. This document is a reference guide for configuration details and production environment setup.

Implementing Producer/Consumer with Spring Kafka

d8lzz1gpw@mozmail.com (kimbenji) — Sat, 10 Jan 2026 00:00:00 +0000

This document provides a step-by-step guide to sending and receiving messages using Spring Kafka.

TL;DR

Producer: Synchronous/asynchronous message sending with KafkaTemplate, Partition assignment using Key

Consumer: Message reception with @KafkaListener, batch processing and pattern subscription support

Manual Commit: Explicit commit after processing completion with Acknowledgment

Error Handling: Retry and Dead Letter Topic configuration with @RetryableTopic

Before You Begin#

Item	Requirement
Target Audience	Backend developers who want to use Kafka in Spring Boot applications
Prerequisites	Basic Java syntax, Spring Boot fundamentals, Kafka basic concepts
Prior Completion	Quick Start example completed, Environment Setup configuration done
Estimated Time	About 30 minutes

Platform-specific Notes
Windows Users: Use gradlew.bat instead of ./gradlew in commands.

Order System

d8lzz1gpw@mozmail.com (kimbenji) — Sat, 10 Jan 2026 00:00:00 +0000

Implement an event-driven order system closer to real-world applications. In this example, we process the entire flow from order creation to delivery completion using Kafka events, and learn about order guarantee using Message Keys and extension patterns utilizing multiple Consumer Groups.

TL;DR

Event-driven Architecture: Convert REST API requests to Kafka events for asynchronous processing

Message Key: Use orderId as Key to guarantee ordering of events for the same order

State Machine: State transitions in order: CREATED -> PAID -> SHIPPED -> DELIVERED

Extension Pattern: Multiple Consumer Groups independently subscribe to the same Topic

Target Audience and Prerequisites#

Item	Description
Target Audience	Backend developers looking to build event-driven systems
Prerequisites	Spring Boot fundamentals, Kafka basic concepts, Basic Examples completed
Required Environment	Kafka running via Docker, JDK 17+, Gradle
Estimated Time	About 45 minutes

All code examples on this page use the following common imports. The implementation centers around Spring Kafka’s KafkaTemplate and @KafkaListener, with JSON serialization handled through Jackson ObjectMapper.

Microservices Integration

d8lzz1gpw@mozmail.com (kimbenji) — Sat, 10 Jan 2026 00:00:00 +0000

Implement event-driven communication using Kafka in a microservices environment.

TL;DR

Event Chaining: Event propagation in order: Order -> Payment -> Shipment -> Notification

Correlation ID: Propagate correlation ID for distributed tracing

Saga Pattern: Handle distributed transactions with compensation transactions

Idempotency: Safely handle duplicate messages

Target Audience and Prerequisites#

Item	Description
Target Audience	Developers building event-driven communication in microservices architecture
Prerequisites	Kafka basics, Spring Boot, understanding of Order System example
Required Environment	Docker, JDK 17+, environment capable of running multiple services
Estimated Time	About 60 minutes

Scenario: Order Processing System#

In this example, the Order Service, Payment Service, Shipment Service, and Notification Service exchange events through Kafka. When the Order Service creates an order, it publishes an event to the orders Topic. The Payment Service receives this and processes payment, publishing results to the payments Topic. The Shipment Service receives payment completed events and creates shipments. The Notification Service subscribes to all Topics and sends notifications to customers.