DRAFT: Release notes V4 and interview Nick by FDelporte · Pull Request #85 · Pi4J/pi4j.github.io

FDelporte · 2025-09-22T14:00:29Z

WORK-IN-PROGRESS

content/about/info-v4.md

# Conflicts: # content/_index.md

taartspi

two comments. thanks for all the documentation work.

content/documentation/providers/ffm.md

FDelporte · 2026-01-28T08:26:53Z

content/documentation/providers/ffm.md

@DigitalSmile can you please review this version of the FFM plugin page? Is the info correct regarding the dependencies and permissions scripts?

taartspi · 2026-01-29T00:03:53Z

Looked over that latest files. Looks good

# Conflicts: # content/documentation/io-types/i2c/_index.md # content/documentation/io-types/pwm.md # content/documentation/io-types/serial.md # content/documentation/io-types/spi.md

# Conflicts: # content/about/release-notes.md

Copilot

Pull request overview

This pull request introduces documentation and release notes for Pi4J V4.0.0, which bumps the minimum Java version to 25 and introduces a new FFM (Foreign Function & Memory) API plugin. The PR is marked as DRAFT and includes an interview blog post with Nick Gritsenko about the FFM implementation.

Changes:

Addition of V4 release notes and "What's New in V4" documentation
New interview blog post with Nick Gritsenko discussing the FFM API plugin
Updates to code examples for digital input/output, serial communication, and other IO types
New FFM provider documentation with setup instructions and implementation notes
Java version bumps from 21 to 25 across documentation
Addition of github-readme shortcode for embedding README content from GitHub
Structural improvements including new future ideas section and reorganized content

Reviewed changes

Copilot reviewed 22 out of 29 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
content/about/release-notes.md	Adds comprehensive V4.0.0 release notes with highlights of 400+ commits
content/about/info-v4.md	New page explaining what's new in V4, focusing on FFM plugin
content/_index.md	Updates latest release to V4.0.0 and adds reference to FFM plugin
content/blog/2026/2026-interview-nick-ffm.md	New interview post with Nick Gritsenko about FFM API implementation
content/documentation/providers/ffm.md	New comprehensive FFM provider documentation with setup instructions
content/documentation/providers/_index.md	Adds FFM to provider list with placeholder pros/cons
content/documentation/io-types/digital-input.md	Updates digital input example to modern syntax
content/documentation/io-types/digital-output.md	Updates digital output example to modern syntax
content/documentation/io-types/serial.md	Removes deprecated serial code, adds reference to jSerialComm examples
content/getting-started/java-development-on-the-raspberry-pi-with-vsc.md	Updates Java version from 21 to 25
themes/hugo-theme-learn/layouts/shortcodes/github-readme.html	New shortcode for embedding GitHub README content
content/architecture/about-the-code/*	Updates build instructions and download sources for Java 25
static/assets/documentation/serial/*.png	New image assets for serial communication examples

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Copilot · 2026-02-20T10:43:23Z

content/about/info-v4.md

+
+The goal of this bump to V4 is to enable the use of the Foreign Function & Memory (FFM) API in Pi4J. This FFM API has been introduced in OpenJDK 22 and simplifies the use of native libraries in Java. And native libraries are "the heart" of the Pi4J project as they provide the connection between your Java code and the hardware.
+
+Thanks to the contributions by [Nick Gritsenko (aka DigitalSmile)](https://github.com/DigitalSmile) in [pull request #458](https://github.com/Pi4J/pi4j/pull/458), a complete new plugin got added to Pi4J. Read more about the work by Nick in this [interview](/blog/2025/2025????-interview-nick-ffm/).


The blog post link appears incomplete with "2025????" in the URL. This should be replaced with the actual date to match the blog post file name "2026-interview-nick-ffm.md" (which is dated 2026-02-20).

Suggested change

Thanks to the contributions by [Nick Gritsenko (aka DigitalSmile)](https://github.com/DigitalSmile) in [pull request #458](https://github.com/Pi4J/pi4j/pull/458), a complete new plugin got added to Pi4J. Read more about the work by Nick in this [interview](/blog/2025/2025????-interview-nick-ffm/).

Thanks to the contributions by [Nick Gritsenko (aka DigitalSmile)](https://github.com/DigitalSmile) in [pull request #458](https://github.com/Pi4J/pi4j/pull/458), a complete new plugin got added to Pi4J. Read more about the work by Nick in this [interview](/blog/2026/2026-02-20-interview-nick-ffm/).

Copilot · 2026-02-20T10:43:24Z

content/documentation/providers/ffm.md

+   </dependency>
+   ```
+
+When using FFM API functionality added to Java in version 22, you will be alerted at startup of the applicatoin with this message:


Typo: "applicatoin" should be "application".

Suggested change

When using FFM API functionality added to Java in version 22, you will be alerted at startup of the applicatoin with this message:

When using FFM API functionality added to Java in version 22, you will be alerted at startup of the application with this message:

Copilot · 2026-02-20T10:43:24Z

content/architecture/about-the-code/download-sources.md

-* In the root of pi4j run `mvn clean install`
+* Checkout the `develop` branch of the [pi4j repository](https://github.com/Pi4J/pi4j).
+* Use a JDK version 25 or newer, e.g. `sdk use java 25.0.1-zulu`.
+* In the root of the `pi4j directory, run `mvn clean install`.


Missing closing backtick in the sentence. The text "In the root of the pi4j directory, run mvn clean install." should be "In the root of the pi4jdirectory, runmvn clean install`."

Suggested change

* In the root of the `pi4j directory, run `mvn clean install`.

* In the root of the `pi4j` directory, run `mvn clean install`.

Copilot · 2026-02-20T10:43:24Z

content/documentation/io-types/digital-input.md

 ```java
 input.addListener(e -> {
-    if (e.state() == DigitalState.HIGH) {
+    if (e.state() == DigitalState.LOW){


In the digital input example, the logic appears reversed. The listener checks if (e.state() == DigitalState.LOW) and then prints "Button is pressed". However, the button is configured with PULL_DOWN resistor on line 25. With a pull-down configuration, when the button is not pressed, the pin reads LOW, and when pressed (connected to 3.3V), it reads HIGH. The condition should be if (e.state() == DigitalState.HIGH) to correctly detect when the button is pressed.

Suggested change

if (e.state() == DigitalState.LOW){

if (e.state() == DigitalState.HIGH){

Copilot · 2026-02-20T10:43:24Z

content/about/release-notes.md

+
+### 2025-02-20 - V4.0.0
+
+This is a big release with almost 400 commits and 300+ files added/changed...! **Pi4J V4 introduces the new [FFM plugin](/documentation/provider/ffm) and bumps the Java version to 25**. The FFM plugin makes use of the now Foreign Function & Memory API (FFM) to access the GPIOs. The FFM API got introduced in Java 22 with [JEP 454](https://openjdk.org/jeps/454).


The link path has a typo. The text shows "/documentation/provider/ffm" but based on the file structure it should be "/documentation/providers/ffm" (plural "providers").

Suggested change

This is a big release with almost 400 commits and 300+ files added/changed...! **Pi4J V4 introduces the new [FFM plugin](/documentation/provider/ffm) and bumps the Java version to 25**. The FFM plugin makes use of the now Foreign Function & Memory API (FFM) to access the GPIOs. The FFM API got introduced in Java 22 with [JEP 454](https://openjdk.org/jeps/454).

This is a big release with almost 400 commits and 300+ files added/changed...! **Pi4J V4 introduces the new [FFM plugin](/documentation/providers/ffm) and bumps the Java version to 25**. The FFM plugin makes use of the now Foreign Function & Memory API (FFM) to access the GPIOs. The FFM API got introduced in Java 22 with [JEP 454](https://openjdk.org/jeps/454).

Copilot · 2026-02-20T10:43:25Z

content/_index.md

 * [V3.X.X](/about/info-v3): Based on Pi4J 2.8.0 and Java 21.
  * Please [read this blog post for more info](/blog/2025/20250211-welcome-java-21/).
+* [V4.X.X](/about/info-v4): Based on Pi4J 3.0.3 and Java 25, introducing the [FFM plugin](/documentation/providers/ffm/).
+    * Please [read this interview with Nick Gritsenko (aka DigitalSmile) for more info](/blog/2025/2025????-interview-nick-ffm/).


The blog post link appears incomplete with "2025????" in the URL. This should be replaced with the actual date to match the blog post file name "2026-interview-nick-ffm.md" (which is dated 2026-02-20).

Suggested change

* Please [read this interview with Nick Gritsenko (aka DigitalSmile) for more info](/blog/2025/2025????-interview-nick-ffm/).

* Please [read this interview with Nick Gritsenko (aka DigitalSmile) for more info](/blog/2026/20260220-interview-nick-ffm/).

Copilot · 2026-02-20T10:43:25Z

content/documentation/providers/_index.md

+    * ...
+  * Contra
+    * ...


The Pro/Contra sections for the FFM provider are empty with just "...". These should either be filled in with actual content or removed if not yet determined. Since this is a major new feature, having these benefits and limitations documented would be valuable.

Suggested change

* ...

* Contra

* ...

* Uses Java's Foreign Function & Memory (FFM) API instead of JNI for native access

* Reduces native glue code and simplifies deployment of native libraries

* Designed as a modern, future‑oriented provider for newer Java runtimes

* Contra

* Requires a recent Java version that supports the FFM API (Project Panama)

* Newer provider that may not yet cover all I/O use cases supported by longstanding providers

Copilot · 2026-02-20T10:43:25Z

content/about/release-notes.md

+
+Requires Java 25, see [What's New in V4](/about/info-v4/) for more info.
+
+### 2025-02-20 - V4.0.0


The release date format is inconsistent. Line 12 shows "2025-02-20" in the heading but line 7 in the main index shows "2025-02-20" as well. However, the blog post about V4 is dated 2026-02-20. This date discrepancy needs to be resolved for consistency.

Copilot · 2026-02-20T10:43:25Z

content/about/release-notes.md

+
+Thanks to contributions by [@DigitalSmile](https://github.com/DigitalSmile), [@IAmNickNack](https://github.com/IAmNickNack), [@stefanhaustein](https://github.com/stefanhaustein), [@taartspi](https://github.com/taartspi), [@eitch](https://github.com/eitch), [@fdelporte](https://github.com/fdelporte).
+
+Detailed list of all the changes: https://github.com/Pi4J/pi4j/compare/3.0.3...4.0.0


Incorrect reference to GitHub compare URL. The text "Detailed list of all the changes: Pi4J/pi4j@3.0.3...4.0.0" should use the correct tag format. Based on the pattern, it should likely be "v3.0.3...v4.0.0" with the 'v' prefix for version tags.

Suggested change

Detailed list of all the changes: https://github.com/Pi4J/pi4j/compare/3.0.3...4.0.0

Detailed list of all the changes: https://github.com/Pi4J/pi4j/compare/v3.0.3...v4.0.0

Release notes V4 and interview Nick (WIP)

2f9b7a2

FDelporte requested review from eitch and taartspi September 22, 2025 14:00

FDelporte added 3 commits September 22, 2025 16:03

Release notes V4 and interview Nick (WIP)

d15495b

Release notes V4 and interview Nick (WIP)

14998ce

Release notes V4 and interview Nick (WIP)

5eba1a3

eitch approved these changes Sep 22, 2025

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content/about/info-v4.md Outdated Show resolved Hide resolved

Merge branch 'main' into release/V4.0.0

b3171e8

FDelporte changed the title ~~Release notes V4 and interview Nick~~ DRAFT: Release notes V4 and interview Nick Sep 22, 2025

FDelporte and others added 21 commits September 23, 2025 14:51

Release notes V4 and interview Nick (WIP)

85606cf

Merge branch 'main' into release/V4.0.0

16a29cb

# Conflicts: # content/_index.md

Merge

abc5baf

Interview improvements

efad347

Added some information on permissions.

315deb7

Remove double content

42b1c08

Add Devoxx

933395b

Merge branch 'main' into release/V4.0.0

456bee5

Merge branch 'main' into release/V4.0.0

45067ba

Replace content on the website with README content from GitHub

92d626d

Added checker tool info for I2C, SPI, PWM, Serial

7182614

Merge branch 'main' into release/V4.0.0

845351a

Merge branch 'main' into release/V4.0.0

c7a7c53

Bump Java version to 25

c6eb6d2

Reworking example code to match V4: IO paramater changes

c7cb653

Merge branch 'main' into release/V4.0.0

ff79915

Prepare V4 release notes

16976bf

Add link to DigiKey PWM article

0ddf246

V4 release notes

e996f2e

Update serial example

a7f654c

Extend interview

a20bf0c

Frank Delporte and others added 3 commits January 20, 2026 20:27

Merge branch 'main' into release/V4.0.0

d5dea89

Interview Nick typos

9863e23

Link to JBang blog

7d1b0a1

taartspi requested changes Jan 28, 2026

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content/documentation/providers/ffm.md Outdated Show resolved Hide resolved

content/documentation/providers/ffm.md Show resolved Hide resolved

Improve FFM page

02d5173

FDelporte commented Jan 28, 2026

View reviewed changes

Frank Delporte and others added 5 commits January 29, 2026 19:41

Merge branch 'main' into feature/readme-include

cb8377c

# Conflicts: # content/documentation/io-types/i2c/_index.md # content/documentation/io-types/pwm.md # content/documentation/io-types/serial.md # content/documentation/io-types/spi.md

Merge branch 'feature/readme-include' into release/V4.0.0

4444a31

Extending V4 info

0f54978

Finish release notes V4

e427648

Merge remote-tracking branch 'origin/release/V4.0.0' into release/V4.0.0

31c1b03

# Conflicts: # content/about/release-notes.md

FDelporte marked this pull request as ready for review February 20, 2026 10:38

Copilot AI review requested due to automatic review settings February 20, 2026 10:38

Copilot started reviewing on behalf of FDelporte February 20, 2026 10:39 View session

FDelporte merged commit 77cf0a9 into main Feb 20, 2026
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Copilot AI reviewed Feb 20, 2026

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FDelporte deleted the release/V4.0.0 branch February 20, 2026 11:54


		The goal of this bump to V4 is to enable the use of the Foreign Function & Memory (FFM) API in Pi4J. This FFM API has been introduced in OpenJDK 22 and simplifies the use of native libraries in Java. And native libraries are "the heart" of the Pi4J project as they provide the connection between your Java code and the hardware.

		Thanks to the contributions by [Nick Gritsenko (aka DigitalSmile)](https://github.com/DigitalSmile) in [pull request #458](https://github.com/Pi4J/pi4j/pull/458), a complete new plugin got added to Pi4J. Read more about the work by Nick in this [interview](/blog/2025/2025????-interview-nick-ffm/).

	When using FFM API functionality added to Java in version 22, you will be alerted at startup of the applicatoin with this message:
	When using FFM API functionality added to Java in version 22, you will be alerted at startup of the application with this message:

	* In the root of the `pi4j directory, run `mvn clean install`.
	* In the root of the `pi4j` directory, run `mvn clean install`.

	if (e.state() == DigitalState.LOW){
	if (e.state() == DigitalState.HIGH){


		### 2025-02-20 - V4.0.0

		This is a big release with almost 400 commits and 300+ files added/changed...! Pi4J V4 introduces the new [FFM plugin](/documentation/provider/ffm) and bumps the Java version to 25. The FFM plugin makes use of the now Foreign Function & Memory API (FFM) to access the GPIOs. The FFM API got introduced in Java 22 with [JEP 454](https://openjdk.org/jeps/454).

	* Please [read this interview with Nick Gritsenko (aka DigitalSmile) for more info](/blog/2025/2025????-interview-nick-ffm/).
	* Please [read this interview with Nick Gritsenko (aka DigitalSmile) for more info](/blog/2026/20260220-interview-nick-ffm/).

-    * ...
-  * Contra
-    * ...
+    * Uses Java's Foreign Function & Memory (FFM) API instead of JNI for native access
+    * Reduces native glue code and simplifies deployment of native libraries
+    * Designed as a modern, future‑oriented provider for newer Java runtimes
+  * Contra
+    * Requires a recent Java version that supports the FFM API (Project Panama)
+    * Newer provider that may not yet cover all I/O use cases supported by longstanding providers


		Requires Java 25, see [What's New in V4](/about/info-v4/) for more info.

		### 2025-02-20 - V4.0.0


		Thanks to contributions by [@DigitalSmile](https://github.com/DigitalSmile), [@IAmNickNack](https://github.com/IAmNickNack), [@stefanhaustein](https://github.com/stefanhaustein), [@taartspi](https://github.com/taartspi), [@eitch](https://github.com/eitch), [@fdelporte](https://github.com/fdelporte).

		Detailed list of all the changes: https://github.com/Pi4J/pi4j/compare/3.0.3...4.0.0

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