DesignPatterns on JAVAPRO International

Are Classic Design Patterns Still Valid With Modern Java?

Thu, 23 Jul 2026 07:00:03 +0000

The classic GoF design patterns helped developers build maintainable object-oriented software for a long time. In the past years the languages, like Java, have changed a lot; they evolved! What was a design pattern back then became a language feature today. This article analyses which patterns are still needed and which became obsolete.

Once upon a time…

Object-Oriented Programming

Object-oriented programming emerged with the invention of Simula 67. Ole-Johan Dahl and Kristen Nygaard invented Simula 67 while working at the Norwegian Computing Center in Oslo to run simulations. A few years later Alan Kay et al. invented Smalltalk as a purely object-oriented programming language. In the 80s, C++ brought the breakthrough in the mainstream for object-oriented programming. The first large-scale object-oriented systems were developed. In the 90s, object-oriented programming was the dominating programming paradigm.

Open-Core with Core Java and Vaadin — Part 2

Sat, 23 May 2026 11:33:42 +0000

Editions, runtime, and quality assurance.

All source code presented here is published on GitHub and available at https://3g3.eu/naityh.

Recap of part one

The first part of this article developed the abstract mechanics of the open-core application. From two independent Maven projects with strictly asymmetric dependency direction, a deliberately slim extension API with the contribution types RouteContribution, MenuContribution, NavbarContribution, and CounterEventListener, a FeatureRegistry that discovers its contributions via the Java standard library’s ServiceLoader, and a Vaadin integration consisting of MainLayout and OpenCoreRouteInitializer, an apparatus is now in place that can accept arbitrary contributions in ordered form, without the core needing to know their identity.

Open-Core with Core Java and Vaadin — Part 1

Fri, 22 May 2026 11:33:04 +0000

Architecture, extension API, and Vaadin integration.

1. Introduction and motivation

The open-core model is often reduced in discussion to questions of licensing or commercial positioning. An open-source variant of a piece of software is complemented by a commercially distributed variant that brings additional features. Anyone who actually wants to implement such a separation in an existing codebase quickly discovers that the real difficulty lies neither in the licence text nor in the choice of repository, but in the code’s architecture.