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.
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Apache Kafka Basics
- Introduction to Apache Kafka
- Intro to Apache Kafka with Spring
- Introduction to Kafka Connectors
- Configuring Kafka SSL Using Spring Boot
- bootstrap-server in Kafka Configuration
- Dynamically Managing Kafka Listeners in Spring Boot
- Connect to Apache Kafka Running in Docker
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Apache Kafka Topics
- Understanding Kafka Topics and Partitions
- Kafka Topic Creation Using Java
- Guide to Purging an Apache Kafka Topic
- Get the Number of Messages in an Apache Kafka Topic
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Apache Kafka Consumer
- Read Data From the Beginning Using Kafka Consumer API
- Difference Between GroupId and ConsumerId in Apache Kafka
- Manage Kafka Consumer Groups
- Kafka Streams With Spring Boot
- Spring Kafka: Configure Multiple Listeners on Same Topic
- How to Subscribe a Kafka Consumer to Multiple Topics
- Implementing Retry in Kafka Consumer
- Commit Offsets in Kafka
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Apache Kafka Producer
- Sending Data to a Specific Partition in Kafka
- Is a Key Required as Part of Sending Messages to Kafka?
- Send Large Messages With Kafka
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Apache Kafka Headers and Messages
- View Kafka Headers in Java
- Add Custom Headers to a Kafka Message
- Ensuring Message Ordering in Kafka: Strategies and Configurations
- Exactly Once Processing in Kafka with Java
- Custom Serializers in Apache Kafka
- How to Catch Deserialization Errors in Spring-Kafka?
- Dead Letter Queue for Kafka With Spring
- Configuring Message Retention Period in Apache Kafka
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Apache Kafka Testing
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