Wim De Troyer on foojay.io - Friends of OpenJDK

The Visitor Pattern - 'Revisited' using Data Oriented Programming techniques

Wed, 26 Nov 2025 10:38:43 +0000

Introduction

Design patterns are great, they standardize solutions for common programming problems so you don’t shoot yourself in the foot or reinvent the wheel.

However, some might argue that some design patterns only exist in a programming language because that language lacks a way to elegantly and efficiently express it in its syntax.

For example, the Strategy pattern is a design pattern that enables selecting algorithms at runtime. Taking the example of different strategies of tax calculation, let’s see what an implementation looked like before java 8:

Foojay Podcast #66: Let's Talk About Java Code!

Tue, 11 Feb 2025 08:24:06 +0000

In this Foojay podcast, we dive into a few articles that were published recently and focus on code.

Igor Kulakov of JetBrains gives us his insights into the tool he created to find duplicate content in documentation.

Rijo Sam explains how you can generate real random values and how he created a train departure display.

Maxillian Arruda explains in a very detailed post the different ways to construct a complex Java object.

And we start with Wim De Troye about the code changes he had to do in a project that got upgraded from Spring Boot 2 to 3.

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The proper way to define configuration properties in Spring

Tue, 07 Jan 2025 16:55:31 +0000

Introduction

I recently did a (long overdue) migration from Spring Boot 2 to 3 on one of our larger applications.

Something that surprised me was that classes marked with @ConfigurationProperties had properties that were properly bound when running in Spring Boot 2 but were no longer bound after the upgrade.

Luckily, the automated testing suite caught this issue at run time , but it’s obvious that such a thing silently failing can be quite problematic.