Foojay on foojay.io - Friends Of OpenJDK

Diagrams as Code: Mermaid Support on the new Foojay

Thu, 24 Sep 2026 00:00:00 +0000

Some things are much easier to show than to describe. A request travelling through three services, a class hierarchy, the states a connection moves through: a paragraph explaining it takes real effort to write and still leaves the reader assembling the picture themselves.

The usual answer is to open a drawing tool, export a PNG, and drop it in the article folder. That works, and it is what most Foojay articles have done so far. It also means the diagram is now a binary file that nobody can review, nobody can correct a typo in, and nobody can update without finding the original file again, assuming they still have it.

AsciiDoc Support on the new Foojay

Wed, 23 Sep 2026 00:00:00 +0000

Markdown is a good default. It is easy to write, everybody already knows it, and for most articles it is exactly enough.

For some articles it is not. If you have ever wanted to put a caption on a code block, number the interesting lines and explain them underneath, or set a warning apart from the paragraph before it, you have found the limits of Markdown.

Large parts of the Java ecosystem document in AsciiDoc for exactly this reason. So posts here on the new Hugo-driven Foojay, can now be written in it too. Thanks to Brice Dutheil for requesting this feature, and for naming exactly which parts of it he uses. And of course, this post is written in AsciiDoc to show it off!

Announcing The New Foojay

Tue, 22 Sep 2026 00:00:00 +0000

Foojay has moved, but the address stays exactly where it was, just like every URL you have bookmarked, linked or cited. Everything behind that address is new. Foojay is now a static site, its entire content lives in a public Git repository, and publishing an article is a pull request.

If you only read one paragraph: nothing you have written has moved, and nothing you need to do has changed, except if you want to contribute content.

Featured Foojay Authors for September 2026: Marit van Dijk and Graeme Robinson

Mon, 07 Sep 2026 08:38:56 +0000

Foojay wouldn’t exist without the many contributions from its community, whether it’s a single post or an ongoing stream of knowledge sharing. That’s why we highlight two of them each month as Featured Authors. After Igor and Steve in July, and Cristobal and Shai in August, September belongs to Marit van Dijk and Graeme Robinson. Want to read more from either of them? Click their name to visit their Foojay author page, where you’ll find their full list of posts.

Featured Foojay Authors for July and August 2026

Tue, 28 Jul 2026 09:05:30 +0000

Foojay wouldn’t exist without the many contributions from its community, whether it’s a single post or an ongoing stream of knowledge sharing. That’s why we’ve started highlighting two of them each month as Featured Authors. We kicked this off in July with Igor and Steve, and this post covers both our July and August (Cristobal and Shai) featured authors. Want to read more from any of them? Just click their name to visit their Foojay author page, where you’ll find their full list of posts. We’ll be back with the next update at the beginning of September.

Foojay Podcast #100: Java Podcasters on Why They Started, What Broke, and What They Learned

Mon, 13 Jul 2026 07:05:59 +0000

Foojay Podcast hits episode 100. No plan, no roadmap. It just happened. To mark the occasion, Frank turned the microphone around and invited other podcasters: Adam Bien (airhacks.fm), Jennifer Reif (Breaktime Tech Talks), Kadi McKean and Steve Pool (10xInsights), and Oumaima Zerouali (JCast). Same three questions for each: why did you start, what broke, and what did you learn?

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A Week of Housekeeping: What Changed on Foojay.io

Mon, 06 Jul 2026 10:04:00 +0000

Running a community website is a bit like maintaining a codebase: the content that matters most is never completely done. And if you don’t schedule regular housekeeping, things can get outdated… Last week, we did some cleanup, restructuring, and updating. Here’s an overview of what changed.

The top menu needed some restructuring…

The News menu now focuses purely on what it says: Daily News, the Foojay Podcast, the JC-AI Newsletter by Miro Wengner, the new Foojay.io AI Portal, and the Event Calendar. The AI Portal is a recent addition we hadn’t properly surfaced before. It collects AI-related resources and tooling for Java developers, so it deserves its own slot in the navigation.

Getting Started with Exposed: Kotlin ORM Made Simple

Mon, 06 Jul 2026 03:39:00 +0000

Introduction

For quite some time, I have been a huge fan of and fascinated by JetBrains products, tools, and libraries because of their masterful craftsmanship in product creation and their pristine focus on building high-quality developer tools.

Even more excitingly, JetBrains Java Annotated Monthly newsletters have featured most of the technical articles I wrote for Foojay on topics such as Java, Spring, Spring Boot 4, and OpenRewrite.

Recently, one Kotlin Domain-Specific Language (DSL) library caught my attention. I immediately tried converting my existing Spring Boot 4 application from Java to Kotlin using Exposed, an ORM framework for Kotlin. Kotlin SQL Libary

JCast

Mon, 04 May 2026 08:00:40 +0000

The Java community thrives on sharing knowledge and experiences. Most content is in English, which works well for many developers. However, there’s something special about discussing complex topics in your native language. The nuances. The humor. The ability to express yourself freely without translating your thoughts first.

That’s why we created JCast, a podcast for the Dutch-speaking developer community. Moreover, today we’re excited to launch Season 2!

Season 2 Starts with Frank Delporte

For our second season opener, we sat down with Frank Delporte. He’s well-known in the Java community as a Java Champion. Additionally, he’s a Java Developer, Technical Writer at Azul, Blogger, and Author of “Getting started with Java on Raspberry Pi”. Furthermore, he’s a Pi4J Contributor.

How I Automated Weekly Twitter/X Posts With Java, JBang and GitHub Actions

Tue, 14 Apr 2026 16:05:06 +0000

Every Monday at 10 AM Eastern, @javaevolved now tweets a modern Java pattern — automatically. No manual steps, no third-party services, no cron servers. Just a GitHub Actions workflow, a couple of JBang scripts, and the Twitter API.

Here’s how it works, and how you can do the same for your own project.

The Problem

Java Evolved is a static site with 113 code patterns showing the old way vs. the modern way to write Java. Each pattern has a title, summary, old/modern approach labels, JDK version, and a link to its detail page.

The Java in Education Catalog Now Has a Beautiful Home

Fri, 27 Mar 2026 13:17:41 +0000

A few weeks ago, Igor De Souza shared Bringing Java Closer to Education: A Community-Driven Initiative here on Foojay. It’s something we started together to gather Java educational resources in one place, making it easier for mentors, educators, and learners to discover what’s out there.

But let’s be honest: a GitHub README, while perfectly functional, is not exactly the most inviting front door for educators who aren’t already deep in the coding ecosystem. That’s now fixed…

JC-AI Newsletter #11

Tue, 09 Dec 2025 16:12:01 +0000

Fourteen days have passed, and it is time to present a fresh collection of readings that could influence developments in the field of artificial intelligence.

This newsletter explores the evolution of agentic AI systems, provides valuable insights into the Chain-of-Thought (CoT) approach, Vibe coding, and discusses the pattern-matching capabilities of LLMs. The newsletter features an insightful interview with Stuart J. Russell, known for his significant contributions to the AI field. Even more exciting is the published paper by Apple researchers titled ‘The Illusion of Thinking…’ and several immediate reactions to the authors’ conclusions, which allow newsletter readers to observe current research challenges and scientific community responses. This provides readers with a vital picture of the state-of-the-art in AI research.

JC-AI Newsletter #10

Wed, 26 Nov 2025 18:39:40 +0000

Fourteen days have passed, and it is time to present a fresh collection of readings that could influence developments in the field of artificial intelligence.

This newsletter focuses on examining how agentic AI systems improve accuracy, tutorials on agentic system architecture, and importnat security challenges arising from increased not only from agentic AI systems adoption. This edition of the AI newsletter includes compelling discussions and interviews about the future of AI and approaches.

JC-AI Newsletter: Easy Access to Expanding Challenges

Tue, 04 Nov 2025 18:13:33 +0000

A few months ago, I launched the AI Newsletter to provide a minimally biased perspective on the growing challenges surrounding artificial intelligence.

My primary motivation was and remains to be serving the community not only by showing how to use and access specific services for utilizing Large Language Models, but also by support a deeper understanding of the broader artificial intelligence landscape.

Many of the core challenges that have emerged around LLMs have not been and still not properly addressed, often omitted due to their uncomfortable implications.

Foojay Podcast #70: Celebrating 5 Years of Foojay

Fri, 25 Apr 2025 08:00:00 +0000

On April 25, 2020, Geertjan Wielenga published the first Foojay post. Yes, we are celebrating 5 years since the Friends Of OpenJDK website launch! Today, more than 1,600 posts are on the site, written by over 250 authors. And there is much more to discover within the Foojay world…

In this podcast, we look at how Foojay started with founder Geertjan Wielenga. We’ll also hear from Gerrit Grunwald about how Foojay’s Disco API has become part of your daily work without you realizing it. We also have several of our regular authors and podcast guests who share how Foojay has influenced them (and vice versa).

Foojay Podcast #64: Interviews at JFall about opensource, OpenJDK evolutions, Project Loom, JVM,...

Mon, 23 Dec 2024 10:51:20 +0000

Let’s wrap up this year with more interviews from the JFall conference.

In this episode you’ll learn more about Foojay, JVM internals and writing your own programming language, Project Loom and structured concurrency, learning at conferences, code reviews, creating desktop applications with Java, infrastructure as code, JUG Noord, and much more!

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Foojay.io At JFall 2024 (And The Winner Is...)

Tue, 12 Nov 2024 08:47:26 +0000

Last week JFall—the “Biggest Java Conference of the Netherlands”—took place. Foojay.io, the Friends Of OpenJDK, were there in full force, including a booth with stickers and other swag, as well as Frank Delporte with his popular Foojay.io Podcast, doing live interviews with attendees.

Not only Frank was present throughout the day, doing interviews for upcoming podcast episodes, but so was his 14-year-old son Vik (in yellow sweater in the pic above), handling the technical side and directing the interviews like a true and enthusiastic professional.

Friends Of OpenJDK Hangout at FOSDEM 2024

Mon, 29 Jan 2024 10:20:42 +0000

FOSDEM is here again, this coming weekend. Many will remember the great hangout Friends Of OpenJDK had at Bier Centraal in Brussels last year.

Well, that was a great experience and all those connected in any way to OpenJDK, whether speaking or not at FOSDEM, are extremely welcome to spend time with the Friends Of OpenJDK community on Saturday evening at the same location, Bier Centraal (Anspachlaan 37).

https://maps.app.goo.gl/7w4NY2QLCSVMdoDz5

Interview with Gokul Chandrasekaran, the creator of JDoodle

Mon, 08 Jan 2024 12:08:12 +0000

In two previous posts, we explained how you can add executable Java code to your posts here on Foojay, including code with dependencies, by using JDoodle.

To achieve this full integration, we got Gokul Chandrasekaran’s support to use the plugin version, and he also gave us some insight into the history and development of JDoodle.

Thanks, Gokul for your support in bringing an online Java editor to Foojay! Can you introduce yourself,please?

Integrate executable Java code in your blog posts, part 2: How to use dependencies

Fri, 15 Dec 2023 10:07:55 +0000

In a previous post, we explained how you can add executable Java code to your posts here on Foojay, by using JDoodle. In this post, you will learn how you can extend this with one or more libraries.

Define Dependencies

To integrate Java code in your post or page that needs dependencies, list their Maven coordinates in the shortcode’s libs parameter.

{{< jdoodle libs="mavenlib1,mavenlib2" >}}

 // This is the place to put your Java code

{{< /jdoodle >}}

The shortcode adds Foojay’s own JDoodle client id for you, and that id only works on the Foojay website. Create your own account on the JDoodle site if you want to use this functionality on another website.

Preserving Software Continuity: Empowering Failover Strategies for Uninterrupted Operations

Thu, 16 Nov 2023 07:53:49 +0000

In today’s ever-changing and fast-paced digital landscape, maintaining uninterrupted business continuity is of utmost importance.

Enter Chronicle Services, a robust mechanism dedicated to upholding application integrity even in the face of service disruptions.

Let’s examine the world of failover strategies and explore how they safeguard software continuity.

Stateless vs. Stateful Services

It’s important to appreciate the difference between stateless and stateful services. Your choice of failover approach is highly influenced by this understanding, especially if the aim is to resume services seamlessly from where they were interrupted.

Digma, Apache APISIX, and OpenValue: Foojay.io at JFall 2023

Mon, 13 Nov 2023 22:19:48 +0000

Last week’s JFall 2023 was a high point in the evolution of Foojay.io, the place for Friends Of OpenJDK.

We had a very big booth right by the entrance to the venue, consisting of a large rollout banner featuring all the organizations involved in Foojay.io, a table totally covered in stickers (hundreds, maybe thousands, of Foojay.io stickers, as well as sponsor stickers, such as Digma), and a podcast zone, where Frank spent most of the day recording short podcast interviews with a very wide range of Java enthusiasts attending the event.

Integrate executable Java code in your blog posts

Tue, 07 Nov 2023 14:49:57 +0000

While developing the Foojay Quickstart Java Tutorial, I was looking for an easy way to integrate runnable Java code examples into the Foojay pages and blogs. That’s when I discovered jdoodle.com. I started by using their online editor, but with this blog I want to show you an even easier method to integrate runnable code here on Foojay.

Integration examples

Single file code

To integrate “plain” Java code in your post or page, wrap it in the jdoodle shortcode:

Contributing to Foojay's Java Community Certification

Wed, 04 Oct 2023 07:12:55 +0000

The recent announcement of Foojay’s intention to create a community-driven certification exam for Java software development has spurred a lot of interest. This article explains how any member of the Java community can participate in the creation of tasks for the certification.

In the previous article about the Foojay Developer Certification, we introduced the need for an objective way to measure the skills of Java developers. While there are many assessments and certifications that test the theoretical knowledge of a developer, very few measure the practical ability to write code, find and fix bugs and apply proper design principles. As a community, we have a large collection of de facto best practices and common sense about what makes a developer good at their job. That is why we need your help in creating a certificate that actually communicates a Developer’s skill.

The DiscoAPI Helps You To Find Any OpenJDK Distribution

Tue, 12 Sep 2023 03:42:44 +0000

Did you know Foojay is not only a human-readable OpenJDK knowledge base but also provides the Disco API that lets you search all OpenJDK distributions? And even if you didn’t know, you probably already are using it, as it’s integrated into SDKMAN!, JReleaser, JBang!, Gradle toolchain, Paketo buildpacks,and more.

The Disco API (i.e., the short name for the Universal OpenJDK Discovery API) is a database and API with all the available OpenJDK versions from all distributors, like Corretto, Liberica, Oracle, Temurin, Zulu, and many others. In total, there are now 89352 different packages at the end of August 2023.

Foojay Status Report: July 2023

Mon, 03 Jul 2023 05:20:56 +0000

Since the start of the Friends Of OpenJDK community in April 2020, we’ve had half yearly status reports, providing the highlights of the past half year, together with some stats and analysis, ending with roadmaps for the next upcoming periods.

Note: Here are the earlier reports, from January - June 2021, July - December 2021, and January - June 2022. At that stage, a much stricter cookie policy was implemented, for reasons of the EU’s GDPR and similar, so that the Google Analytics trends which had been very nice until that stage (we had as much traffic in the first half of 2022 as we had for the whole of 2021) were destroyed. Attempts were made to recover or reinstate similar methods for analyzing usage, hence the delay in reports coming out since midway through last year, though these attempts have failed. And if the method for counting usage changes as dramatically as it now has, then it becomes impossible to discuss trend comparisons from before that change and after it. In terms of trends, we now need to start from scratch. Since that is not something that can be repaired, making comparisons between different periods in the past and the current period, as in previous reports, doesn’t make sense anymore.

Introducing the Foojay.io Calendar API

Thu, 22 Jun 2023 06:40:22 +0000

We are excited to share that Foojay is growing and offering additional resources to bring the Java and OpenJDK community together on a global scale.

Several months ago, we launched the Foojay Calendar, an interactive platform that allows individuals to propose Java-related and Kotlin-related and any other OpenJDK-related events and add them to the calendar.

All Foojay members are welcome to submit their events. Once reviewed, the event will be included in the calendar.

Java is Very Fast, If You Don’t Create Many Objects

Thu, 01 Jun 2023 04:45:56 +0000

This article looks at a benchmark passing events over TCP/IP at 4 billion events per minute using the net.openhft.chronicle.wire.channel package in Chronicle Wire and why we aim to avoid object allocations.

One of the key optimisations is creating almost no garbage. Allocation is supposed to be a very cheap operation and garbage collection of very short lived objects is also very cheap.

Does not allocating really make such a difference? What difference does one small object per event (44 bytes) make to the performance in a throughput test where GC pauses are amortised?

Foojay.io at FOSDEM 2023 Trip Report

Mon, 06 Feb 2023 20:58:47 +0000

“What if Simon Ritter’s Friends Of OpenJDK keynote session at FOSDEM entitled ‘After Nearly 30 Years, How Is Java So Popular?’ ends up being held… in an empty room?”

In a nutshell, this was my worst case scenario slash biggest ‘concern’ over the past weeks, narrowly followed by the image of someone taking a pic of Simon in an empty room talking about Java’s popularity.

After all, it’s been several years since the last in-person FOSDEM was held in Brussels, Belgium, so maybe there wouldn’t be that many people. Secondly, the abovementioned keynote session was scheduled at 09:00 AM on a Sunday morning. Also, thirdly, is Java at all still a hot enough topic to attract people at FOSDEM, where there are multiple rooms and tracks competing for attention and attendance, with lots of young fresh faced developers who might prefer spending time in any of the other many rooms.

Foojay Podcast #12: State and Future of the IDEs

Mon, 23 Jan 2023 10:14:45 +0000

In this podcast, we are talking to some of the key people working on different IDEs, Integrated Development Environments.

Those are applications that provide tools to computer programmers for software development.

An IDE typically consists of at least a source code editor, build automation tools, and a debugger.

Let’s learn how these tools evolved, and the challenges they face to stay up-to-date with the many evolutions in Java and all other programming languages.

Foojay on foojay.io - Friends Of OpenJDK

Diagrams as Code: Mermaid Support on the new Foojay

AsciiDoc Support on the new Foojay

Announcing The New Foojay

Featured Foojay Authors for September 2026: Marit van Dijk and Graeme Robinson

Featured Foojay Authors for July and August 2026

Foojay Podcast #100: Java Podcasters on Why They Started, What Broke, and What They Learned

YouTube

Podcast Apps

A Week of Housekeeping: What Changed on Foojay.io

Navigation Reorganised

Getting Started with Exposed: Kotlin ORM Made Simple

Introduction

JCast

Season 2 Starts with Frank Delporte

How I Automated Weekly Twitter/X Posts With Java, JBang and GitHub Actions

The Problem

The Java in Education Catalog Now Has a Beautiful Home

JC-AI Newsletter #11

JC-AI Newsletter #10

JC-AI Newsletter: Easy Access to Expanding Challenges

Foojay Podcast #70: Celebrating 5 Years of Foojay

Foojay Podcast #64: Interviews at JFall about opensource, OpenJDK evolutions, Project Loom, JVM,...

Video

Podcast Apps

Foojay.io At JFall 2024 (And The Winner Is...)

Friends Of OpenJDK Hangout at FOSDEM 2024

Interview with Gokul Chandrasekaran, the creator of JDoodle

Integrate executable Java code in your blog posts, part 2: How to use dependencies

Define Dependencies

Preserving Software Continuity: Empowering Failover Strategies for Uninterrupted Operations

Stateless vs. Stateful Services

Digma, Apache APISIX, and OpenValue: Foojay.io at JFall 2023

Integrate executable Java code in your blog posts

Integration examples

Single file code

Contributing to Foojay's Java Community Certification

The recent announcement of Foojay’s intention to create a community-driven certification exam for Java software development has spurred a lot of interest. This article explains how any member of the Java community can participate in the creation of tasks for the certification.

The DiscoAPI Helps You To Find Any OpenJDK Distribution

Foojay Status Report: July 2023

Introducing the Foojay.io Calendar API

Java is Very Fast, If You Don’t Create Many Objects

Foojay.io at FOSDEM 2023 Trip Report

“What if Simon Ritter’s Friends Of OpenJDK keynote session at FOSDEM entitled ‘After Nearly 30 Years, How Is Java So Popular?’ ends up being held… in an empty room?”

Foojay Podcast #12: State and Future of the IDEs