Design Patterns Series
Last updated: July 29, 2025
Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.
Get started with mocking and improve your application tests using our Mockito guide:
Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.
Get started with understanding multi-threaded applications with our Java Concurrency guide:
Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:
Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.
But these can also be overused and fall into some common pitfalls.
To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:
Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:
Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.
I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.
You can explore the course here:
Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.
Get started with Spring Data JPA through the guided reference course:
Refactor Java code safely — and automatically — with OpenRewrite.
Refactoring big codebases by hand is slow, risky, and easy to put off. That’s where OpenRewrite comes in. The open-source framework for large-scale, automated code transformations helps teams modernize safely and consistently.
Each month, the creators and maintainers of OpenRewrite at Moderne run live, hands-on training sessions — one for newcomers and one for experienced users. You’ll see how recipes work, how to apply them across projects, and how to modernize code with confidence.
Join the next session, bring your questions, and learn how to automate the kind of work that usually eats your sprint time.
In distributed systems, managing multi-step processes (e.g., validating a driver, calculating fares, notifying users) can be difficult. We need to manage state, scattered retry logic, and maintain context when services fail.
Dapr Workflows solves this via Durable Execution which includes automatic state persistence, replaying workflows after failures and built-in resilience through retries, timeouts and error handling.
In this tutorial, we'll see how to orchestrate a multi-step flow for a ride-hailing application by integrating Dapr Workflows and Spring Boot:
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Creational Patterns
- Introduction to Creational Design Patterns
- Automatic Generation of the Builder Pattern with FreeBuilder
- Using the @Singular Annotation with Lombok Builders
- Lombok Builder with Custom Setter
- Lombok @Builder with Inheritance
- Using Lombok’s @Builder Annotation
- Abstract Factory Pattern in Java
- Introduction to AutoFactory
- The Factory Design Pattern in Java
- Singletons in Java
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Structural Patterns
- Proxy, Decorator, Adapter and Bridge Patterns
- The Proxy Pattern in Java
- The Adapter Pattern in Java
- The Decorator Pattern in Java
- Composite Design Pattern in Java
- Facade Design Pattern in Java
- Flyweight Pattern in Java
- The DAO Pattern in Java
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Behavioral Patterns
- Memento Design Pattern in Java
- The Mediator Pattern in Java
- State Design Pattern in Java
- Interpreter Design Pattern in Java
- Visitor Design Pattern in Java
- The Command Pattern in Java
- The Observer Pattern in Java
- Implementing the Template Method Pattern in Java
- Strategy Design Pattern in Java
- Chain of Responsibility Design Pattern in Java
- Apache Commons Chain
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Other Architectural Patterns
- Service Locator Pattern and Java Implementation
- Introduction to Intercepting Filter Pattern in Java
- A Guide to the Front Controller Pattern in Java
- Introduction to the Null Object Pattern
- Spring Cloud Series – The Gateway Pattern
- Testing with Selenium/WebDriver and the Page Object Pattern
- Integration Patterns With Apache Camel
- The DTO Pattern (Data Transfer Object)
- Design Patterns in the Spring Framework
- Saga Pattern in a Microservices Architecture
- A Solid Guide to SOLID Principles
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