In this article, you will learn how to configure tracing for Kafka producer and consumer with Spring Boot and Open Telemetry. We will use the Micrometer library for sending traces and Jaeger for storing and visualizing them. Spring Kafka comes with built-in integration with Micrometer for the KafkaTemplate and listener containers. You will also see how to configure the Spring Kafka observability to add our custom tags to traces. If you are interested in Kafka and Spring Boot, you may find several articles on my blog about it. To read about concurrency with Kafka and Spring Boot read the follow ..read more

In this article, you will learn how to build slim Docker images for your Java apps using Alpine Linux and the jlink tool. We will leverage the latest Java 21 base images provided by Eclipse Temurin and BellSoft Liberica. We are going to compare those providers with Alpaquita Linux also delivered by BellSoft. That comparison will also include security scoring based on the number of vulnerabilities. As an example, we will use a simple Spring Boot app that exposes some REST endpoints. If you are interested in Java in the containerization context you may find some similar articles on my blog. For ..read more

This article will teach you how to build modulith with Spring Boot and use the Spring Modulith project features. Modulith is a software architecture pattern that assumes organizing your monolith app into logical modules. Such modules should be independent of each other as much as possible. Modulith balances monolithic and microservices-based architectures. It can be your target model for organizing the app. But you can also treat it just as a transitional phase during migration from the monolithic into a microservices-based approach. Spring Modulith will help us build a well-structured Sp ..read more

In this article, you will learn how to leverage CRaC to reduce Java startup time and configure it for the app running on Kubernetes. The OpenJDK Coordinated Restore at Checkpoint (CRaC) project was introduced by Azul in 2020. As you probably know, Azul is an organization famous for the OpenJDK distribution called Azul Zulu. Azul shipped an OpenJDK 17 distribution with built-in support for CRaC. Its aim is to drastically reduce the startup time and time to peak performance of Java apps. Micronaut and Quarkus frameworks already support CRaC, while Spring Framework announ ..read more

In this article, you will learn how to implement Spring Boot apps that communicate over gRPC. gRPC is a modern open-source Remote Procedure Call (RPC) framework that can run in any environment. By default, it uses Google’s Protocol Buffer for serializing and deserializing structured data. Of course, we can also switch to other data formats such as JSON. In order to simplify our adventure with gRPC and Spring Boot, we will use a dedicated starter for that. Since there is no officially supported starter for integration between gRPC and Spring Boot, we will choose the most popular third-party pro ..read more

In this article, you will learn how to implement and test reactive Spring Boot apps using Spring WebFlux, R2DBC, and Postgres database. We will create two simple apps written in Kotlin using the latest version of Spring Boot 3. Our apps expose some REST endpoints over HTTP. In order to test the communication between them and integration with the Postgres database, we will use Testcontainers and Netty Mock Server. If you are looking for more guides to Spring Boot 3, you can look at other posts on my blog. In that article, I’m describing how to build a microservices architecture with Spring Boot ..read more

In this article, you will learn how to collect and send the Spring Boot app logs to Grafana Loki. We will use Loki4j Logback appended for that. Loki is a horizontally scalable, highly available log aggregation system inspired by Prometheus. I’ll show how to configure integration between the app and Loki step by step. However, you can also use my auto-configured library for logging HTTP requests and responses that will do all those steps for you. Source Code If you would like to try it by yourself, you may always take a look at my source code. To do that you need to clone my GitHub reposit ..read more

In this article, you will learn how to create, test, and run apps with Spring Cloud Kubernetes, and Spring Boot 3. You will see how to use tools like Skaffold, Testcontainers, Spring Boot Admin, and the Fabric8 client in the Kubernetes environment. The main goal of this article is to update you with the latest version of the Spring Cloud Kubernetes project. There are several other posts on my blog with similar content. You can refer to the following article describing the best practices for running Java apps on Kubernetes. You can also read about microservices with Spring Cloud Kubernetes in t ..read more

In this article, you will learn how to use Spring Boot built-in support for Testcontainers and Docker Compose to run external services in development mode. Spring Boot introduces those features in the current latest version 3.1. Of course, you can already take advantage of Testcontainers in your Spring Boot app tests. However, the ability to run external databases, message brokers, or other external services on app startup was something I was waiting for. Especially, since the competitive framework, Quarkus, already provides a similar feature called Dev Services, which is very useful during my ..read more

This article will teach you how to configure concurrency for Kafka consumers with Spring Boot and Spring for Kafka. Concurrency in Spring for Kafka is closely related to the Kafka partitions and consumer groups. Each consumer within a consumer group can receive messages from multiple partitions. While a consumer inside a group uses a single thread, the group of consumers utilizes multiple threads to consume messages. Although each consumer is single-threaded, the processing of records can leverage multiple threads. We will analyze how to achieve it with Spring Boot and Spring for Kafka. The to ..read more