Java 17 Backend Development: Design backend systems using Spring Boot, Docker, Kafka, Eureka, Redis, and Tomcat

Java 17 Backend Development

Design backend systems using Spring Boot, Docker, Kafka, Eureka, Redis, and Tomcat

Elara Drevyn

Preface

This book offers beginners and backend developers with practical guidance on developing robust server-side applications with Java 17. Each chapter is structured around hands-on examples, real-world challenges, and step-by-step solutions tailored to Java professionals aiming to elevate their expertise in backend systems. It seamlessly transitions through essential development phases, covering everything from foundational elements like object-oriented design and basic REST endpoints to advanced microservices architecture and container orchestration. It covers everything from wiring up databases with Hibernate to managing asynchronous communication with Apache Kafka and securing endpoints with Spring Security. You will gain insight into caching strategies with Redis and diving into techniques to boost performance and reduce database load. It also covers Spring Cloud concepts like Eureka for service discovery and Config Server for centralized management, showing how microservices function cohesively.

The book also covers testing and debugging topics, highlighting modern tools and practices such as JUnit, Mockito, integration tests, and distributed tracing. The book clearly encourages consistent coding standards, efficient concurrency patterns, and a layered approach for verifying logic. As the book moves forward, it clearly illustrates how to maintain code quality and automate deployment workflows using continuous integration and delivery pipelines. Towards the book's end, you will know how to run Java 17 backend applications in production environments, and you will be applying best practices for logging, monitoring, security, and scalability. You will witness how all of these pieces fit together in a coherent ecosystem, whether they are deploying on Tomcat or containerizing with Docker.

In this book you will learn to:

Set up RESTful APIs and data mappings.

Use Spring Security for robust user authentication and role-based access control.

Employ Redis caching techniques to offload databases and enhance performance.

Integrate Kafka to establish asynchronous, high-throughput communication among microservices.

Adopt Spring Cloud tools for configuration, discovery, and gateway-based microservice architectures.

Employ Docker containerization for portable deployments across environments.

Construct CI/CD pipelines to automate testing, building, and delivery of microservices.

Conduct thorough integration testing with real databases, brokers, and external dependencies.

Use debugging tools, logs, and distributed tracing to isolate production issues.

Optimize concurrency, resource usage, and monitoring to handle large-scale backend demands.

Prologue

I know many Java professionals who struggle with bridging the gap between knowing the language fundamentals and writing a production-ready backend. They often find themselves grappling with configuration headaches, performance bottlenecks, and advanced frameworks that appear daunting. I decided to write this book because I've seen these problems time and again. Time and again, I saw talented developers trying to figure out how to adopt microservices, orchestrate containers, or integrate messaging systems, all while staying within deadlines and avoiding excessive complexity.

As I worked on various enterprise projects, I realized that certain patterns repeatedly emerged—connecting to databases with JPA or Hibernate, caching data, deploying with Tomcat or containers, managing configurations in dynamic environments, and ensuring proper testing strategies. There was a clear demand for concrete, step-by-step explanations. Colleagues expressed a clear need for guidance on handling concurrency, implementing security measures, and debugging errors in distributed services. Many felt overwhelmed by the number of libraries and the fast-paced changes in the ecosystem.

I'm sharing my experiences in a direct manner, focusing on how developers can utilize Java 17 effectively for server-side tasks. Each chapter tackles a specific need, from building REST endpoints to handling microservices communications. I show realistic tasks like setting up continuous integration, orchestrating containers, or installing caching solutions. I don't just present theoretical knowledge. I blend real application code with relevant concepts, not ignore them. My background in client-facing platforms convinced me that pushing code to production safely is just as important as writing elegant logic. I devote significant time to explaining testing, debugging, and the final mile of deployment.

While writing, I imagined a Java developer who has wrestled with half-baked solutions or incomplete instructions. I wanted them to see a cohesive path from the first lines of code to a reliable production environment. Throughout this book, I've deliberately chosen language that is accessible and real-world examples that are easy to understand. You will gain the confidence to piece everything together, no matter the size of the system they are creating. Java 17's new features enhance maintainability and performance, and this book shows how they seamlessly integrate into modern backend practices.

Approach backend development with renewed enthusiasm and ability to tackle emerging challenges head-on

- Elara Drevyn

Copyright © 2024 by GitforGits

All rights reserved. This book is protected under copyright laws and no part of it may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without the prior written permission of the publisher. Any unauthorized reproduction, distribution, or transmission of this work may result in civil and criminal penalties and will be dealt with in the respective jurisdiction at anywhere in India, in accordance with the applicable copyright laws.

Published by: GitforGits

Publisher: Sonal Dhandre

www.gitforgits.com

[email protected]

Printed in India

First Printing: December 2024

Cover Design by: Kitten Publishing

For permission to use material from this book, please contact GitforGits at [email protected].

Content

Preface

GitforGits

Acknowledgement

Chapter 1: Introduction to Java 17 and Backend Development

Understanding Java 17 Features

Role of Backend Development

Overview of Backend Technologies

Spring and Spring Boot

Hibernate ORM

RESTful APIs

Security, Caching, Messaging, and Microservices

Introduction to Book Application

Overview of GitforGits Project

Tools and Concepts

Summary

Chapter 2: Setting up Development Environment

Installing Java Development Kit (JDK) 17

Setting up Eclipse IDE

Managing Dependencies with Maven

Project Structure and Version Control

Summary

Chapter 3: Introduction to Spring and Spring Boot

Up and Running with Spring

Getting Started with Spring Boot

Dependency Injection and Inversion of Control

Creating GitforGits Base Application

Summary

Chapter 4: Building RESTful APIs with Spring Boot

Understanding RESTful Web Services

Creating Controllers and Request Mapping

Understanding Controllers

Mapping URLs to Methods

Sample Program: Building a Sample Controller

Handling HTTP Methods and Responses

Role of CRUD Operations

Implementing GET

Implementing POST

Implementing PUT

Implementing DELETE

Handling Errors and Status Codes

Testing Endpoints

Integration with Services and Repositories

Consistency and Documentation

Summary

Chapter 5: Data Persistence with Hibernate ORM and JPA

Configuring Hibernate with Spring Boot

Introducing Hibernate and JPA

Setting up Dependencies and Configuration

Entity Modeling with JPA Annotations

Using Spring Data JPA Repositories

Integrating Repositories into Services

Testing Integration

Handling Schema Evolution and Environments

Advanced JPA Features

Transactions and Consistency

Logging and Monitoring

Defining Entities and Relationships

Implementing Repositories

Summary

Chapter 6: Managing Database Interactions

Database Configuration and Connectivity

Setting Data Source Properties

Verifying Connections

Profile-specific Configurations

Using YAML for Configuration

Adapting to Different Environments

Connection Pooling and Advanced Settings

Testing Connectivity and Queries

Considering Migrations and Environments

Adapting to Other Databases

CRUD Operations with Repositories

Transaction Management

Introduction to @Transactional

Default Transactional Behavior

Controlling Transaction Scope and Isolation

Rollback Rules

Testing Transactions

Performance and Transaction Handling

Combining Transactions with Other Features

Querying with JPQL and Criteria API

Using JPQL for Complex Queries

Criteria API for Dynamic Queries

Summary

Chapter 7: User Authentication and Authorization with Spring Security

Introduction to Spring Security

Implementing Authentication Mechanisms

Role-Based Access Control

Understanding Roles and Authorities

Defining Roles in User Store

Configuring Authorization Rules

Method-Level Security

Evolving Roles and Permissions

Summary

Chapter 8: Caching with Redis

Understanding Caching Concepts

Integrating Redis with Spring Boot

Implementing Caching

Identifying What to Cache

Applying Caching Annotations

Choosing TTL Strategy

Handling Stale Data and Invalidation

Caching Complex Queries and Result Sets

Monitoring and Adjusting Cache Usage

Integrate Caching into CI/CD and Tests

Scaling and Enhancing the Caching Strategy

Summary

Chapter 9: Messaging with Apache Kafka

Setting up Kafka

Installing and Configuring Kafka

Integrating Kafka with Docker

Configuration Considerations and Tuning

Securing and Networking

Linking Kafka to App

Producing and Consuming Messages

Setting up Spring-Kafka Dependency

Creating a Kafka Producer

Creating a Kafka Consumer

Handling Complex Data Formats

Observing Offsets and Consumer Groups

Reliability and Error Handling

Integrating Kafka into App

Defining Event Model

Publishing a BookEvent

Consuming the Event

Logging and Auditing with Kafka

Handling Errors and Retries

Summary

Chapter 10: Microservices Architecture with Spring Cloud

Spring Cloud Overview

Why Microservices?

Key Components of Spring Cloud

Benefits of Integrated Microservices

Setting up a Config Server

Purpose of a Config Server

Creating a Config Server

Connecting to a Configuration Repository

Running the Config Server and Testing

Integrating Microservices with the Config Server

Handling Environment Profiles and Overrides

Registering Microservices with Eureka

Role of Eureka

Installing a Eureka Server

Registering the Microservices

Configuring a Gateway Service

Need of Gateway

Setting up Spring Cloud Gateway

Configuring Routes

Testing and Observability

Summary

Chapter 11: Testing and Debugging Backend Applications

Unit Testing with JUnit and Mockito

Why Unit Testing?

Installing JUnit and Mockito

Writing a Simple JUnit Test

Using Mockito to Mock Dependencies

Advanced Mockito Patterns

Test Organization and Best Practices

Debugging Failures

Integration Testing

Why Integration Testing?

Setting up Testing Environment

Using MockMvc for HTTP-Level Tests

Testcontainers for External Services

Multi-Service Integration

Debugging Techniques

Debugging with Logs and Correlation IDs

Using IDE Debugger

Leveraging Trace Tools for Distributed Systems

Sample Program: Logging Exception with Extra Data

Performance or Memory Profiling

Sample Program: Debugging a Failing Integration Test

Continuous Integration and Delivery

Setting up CI Pipeline

Adding Integration Tests to Pipeline

Implementing CD for Automated Deployments

Managing Environment-specific Config

Monitoring and Rollbacks

Sample Program: Jenkinsfile for a Microservice

Summary

Chapter 12: Deploying Java Backend Applications

Preparing App for Deploy

Choosing Right Build Artifacts

Optimizing Configuration

Preparing Database and External Dependencies

Logging and Monitoring

Security Considerations

Deployment Options

Final Verification before Launch

Deploying to Application Servers

Understanding Tomcat

Building WAR for GitforGits

Deploying WAR to Tomcat

Testing and Managing Deployment

Containerization with Docker

Installing Docker and Basic Commands

Creating Dockerfile

Persisting Data and Volumes

Building Minimal Images

Deploying Containers

Logging and Monitoring in Containers

Summary

Index

Epilogue

GitforGits

Prerequisites

This book is for Java developers, Spring developers, Spring Boot Programmers, web developers, and full-stack developers, as well as anyone interested in exploring the world of Java to improve the back-end of enterprise applications. You'll need some hands-on experience with Java 17 to get the most out of this book.

Codes Usage

Are you in need of some helpful code examples to assist you in your programming and documentation? Look no further! Our book offers a wealth of supplemental material, including code examples and exercises.

Not only is this book here to aid you in getting your job done, but you have our permission to use the example code in your programs and documentation. However, please note that if you are reproducing a significant portion of the code, we do require you to contact us for permission.

But don't worry, using several chunks of code from this book in your program or answering a question by citing our book and quoting example code does not require permission. But if you do choose to give credit, an attribution typically includes the title, author, publisher, and ISBN. For example, Java 17 Backend Development by Elara Drevyn.

If you are unsure whether your intended use of the code examples falls under fair use or the permissions outlined above, please do not hesitate to reach out to us at [email protected]. 

We are happy to assist and clarify any concerns.

Chapter 1: Introduction to Java 17 and Backend Development

Understanding Java 17 Features

The Java programming language has traveled a long and interesting path since its inception in the mid-1990s. An initial release of Java 1.0 arrived around 1995 with a promise of write once, run anywhere that captured the attention of developers who sought more portability in their projects. It began as something that could power applets inside browsers, then gradually found its place in server-side applications, enterprise systems, and various kinds of backend services. Over time, Java 2, Java 5, and later Java 8 introduced new syntactic sugar, improved concurrency models, and functional-style programming through lambdas and streams. By the time Java 11 came around, developers noticed a more rapid release cadence, with new major versions emerging every six months instead of every few years. This shift also introduced the concept of Long-Term Support (LTS) versions, where selected releases receive extended support and stability guarantees. Moving through Java 12, Java 13, and onward, incremental improvements enhanced overall language ergonomics. Java 14, Java 15, and Java 16 added pattern matching, better switch expressions, text blocks, and other features that simplified working with data. By the time we reach Java 17, the community finds a major LTS milestone that many consider to be a sensible baseline for modern server-side coding. Java has not stopped evolving with 17, as more recent versions like Java 18, Java 19, Java 20, Java 21, Java 22, and the emerging Java 23 continue to refine features, expand pattern matching, enhance virtual threads, and integrate new APIs. Each passing version encourages developers to write more expressive, more secure, and more maintainable code, while retaining backward compatibility for older projects that need stability and continuity.

Fig 1.1 Java Version Evolution

A large portion of the Java community gravitates toward Java 17 for several practical reasons, primarily because it represents a stable LTS release that many enterprises trust for building and maintaining production services. With the rapid pace of Java’s six-month release cycle, some releases are not supported for a long period, so enterprises often wait for these LTS versions to ensure that their codebases have a stable foundation for the next several years. Java 17 stands