Emanuel Trandafir

Baeldung on Java

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Testing (10)
Architecture (8)
Data (7)
Spring Boot (5)
Spring WebFlux (4)
Reactive (4)
Persistence (4)
Spring Data (3)
Spring (3)
Maven (3)
Java Streams (3)
Java Concurrency (3)
Docker (3)
Spring AI (2)
Java (2)
DevOps (2)
Web Services (1)
Spring Web (1)
Java Dates (1)
Java Collections (1)
Jakarta EE (1)
Jackson (1)
JSON (1)
JPA (1)
Core Java (1)
Artificial Intelligence (1)

Implementing CQRS with Spring Modulith

Let’s take a fresh look at the CQRS pattern, exploring its benefits and trade-offs in a modular Spring Boot application. We’ll use Spring Modulith to structure our code into clearly separated modules and to enable asynchronous, event-driven communication between them.

This approach is inspired by our colleague Gaetano Piazzolla’s article, where he demonstrates CQRS with Spring Modulith in a product catalog. Here, we’ll adapt the same ideas to a movie ticket booking system and keep the two sides in sync via domain events.

How to Fix Unknown Magic Byte Errors in Apache Kafka

Filed under Data, Spring Boot

“Unknown magic byte” error and other deserialization issues can arise when consuming Avro messages in Kafka. Spring Kafka’s ErrorHandlingDeserializer and publishing to a DLQ topic can help manage poison pill messages like these, ensuring the consumer continues processing without getting stuck.

Transactional Messaging for Microservices Using Eventuate Tram

Filed under Architecture, Data

It’s challenging to maintain data consistency between database operations and messaging. We can make it simpler with the transactional outbox pattern and Eventuate Tram.

Micrometer Observation and Spring Kafka

Filed under Data

Explore the monitoring capabilities provided by Spring Kafka using Micrometer and Spring Boot Actuator. Take a look at the native metrics exposed by Apache Kafka for both producers and consumers, which offer valuable insights into performance, throughput, errors, and latency and those augmented by Spring.

Mocking JDBC for Unit Testing

Filed under Persistence, Testing

Testing code that uses JDBC objects to interact with the database raises important questions about mocking. It’s tempting to use Mockito to stub all the java.sql objects involved in acquiring a JDBC Connection, creating a Statement, executing a query and retrieving the data from the ResultSet. This comes with its own set of problems, though.

Baeldung on Kotlin

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Testing (1)
Kotlin Strings (1)
Kotlin Numbers (1)
Kotlin Basics (1)
Kotlin Arrays (1)

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Database Concepts (1)

Multiple Indexes vs. Multi-Column Indexes

Filed under Database Concepts

Explore database indexes, focusing on the differences between individual and composite indexes.

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