One Query, Complete Object Graphs: Nested DTOs with jOOQ MULTISET

In my previous post about Open Session in View, I explored how this default Spring Boot setting can hide serious performance problems. The N+1 query problem sits behind a system[...]

The Hidden Performance Killer: Understanding Open Session in View in Spring Boot

If you’ve ever wondered why your Spring Boot application feels sluggish under load despite appearing to work perfectly during development, there’s a good chance[...]

An AI-Ready Architecture for Business Applications

Agentic AI is changing how we build software. AI is no longer just a helper that writes small code snippets. It can reason about requirements, generate larger parts of a system,[...]

How to Deploy a Vaadin Application as a WAR on Tomcat 11

If you want to run a Vaadin application on an external servlet container like Apache Tomcat 11, you need to package your application as a WAR (Web Application Archive) instead of[...]

Configuring the Entra Spring Boot Starter Behind a Proxy

I recently encountered a challenge when using the Spring Boot integration for Microsoft Entra (spring-cloud-azure-starter-active-director) behind a corporate proxy. It was a pain[...]

Securing Vaadin Applications with One-Time Token

Logging into an application should be simple for users but still safe and secure. Traditional logins with usernames and passwords work, but they can be inconvenient and sometimes[...]

Secure and Efficient Oracle DB Setup with Spring Boot and Testcontainers

Having one user for creating database objects (DDL) and another for application-level data operations (DML) has many benefits. It improves security, keeps things organized, and[...]

How do you get a Spring Bean without Dependency Injection?

Sometimes, you want to use a Spring Bean in a class that is not a Spring Bean, but then dependency injection doesn’t work. This article shows a way to get around that limitation.

Durable Subscription with JMS and Spring Boot

When using the publish-subscribe domain with JMS we often want to use durable subscriptions. But how can this be done with Spring Boot?

Testing Spring Boot JMS with ActiveMQ Artemis and Testcontainers

Currently, I’m teaching JMS with Spring Boot at the University of Applied Science in Bern, Switzerland. We use Apache ActiveMQ Artemis as the JMS message broker. But how can[...]

Spring boot, angular and JWT authentication

In preparation for a potential customer project, I had to refresh my knowledge of Angular. The best way to do that is to create a small demo application. I used Angular 15 with[...]

Vaadin Keycloak OAuth2 Integration

Keycloak is an open source identity and access management solution. This article shows how to configure Vaadin and Spring Security to use OAuth2 with Keycloak.