OpenJDK's Project Leyden aims to improve the startup and warmup time of Java applications, for now by shifting computation from those phases to the applications' build time. Java 24 ships with ahead-of-time class loading and linking, which is the first step in that direction. In this episode, we learn about that as well as about Leyden's approach to reach its goals and some features that are available in its early access build plus some that aren't.

Nicolai Parlog discusses with Dan Heidinga, who is JVM Runtime Architect at Oracle and, among other things, member of projects Leyden and Valhalla.

In this episode, Ana is joined by Viktor Klang, core JDK architect and author of the Stream Gatherers JDK Enhancement Proposal, to dive into one of the standout features of JDK 24: the Gatherers API.

Viktor explains how Gatherers extend the Java Stream API with custom intermediate operations, why they were added to the platform, and how they can enhance your day-to-day Java development. He also shares practical tips for using the Gatherers API effectively, along with insights into the design process and how community feedback plays a crucial role in shaping future JDK features.

Java leads by example regarding documentation: JavaDoc inspires trust in developers through its transparency on each Java API functionality, and the javadoc tool helps developers generate equally great documentation for their APIs and libraries.

In this episode, Ana hosts Jonathan Gibbons, core contributor and maintainer of JDK tools, to discuss JavaDoc/javadoc developments, focusing on markdown in JavaDoc documentation comments. Given the importance of having code that is as easy to understand as it is functional, Jonathan dives into significant changes in Java’s documentation component and associated tools, how JavaDoc is maintained, code documentation practices, and more.

In this shorter-format pod, Chad talks about JDK 24, preview features, and more.

Show Notes

JEP 11: Incubator Modules
https://openjdk.org/jeps/11

JEP 12: Preview Features
https://openjdk.org/jeps/12

Using the Preview Features Available in the JDK
https://dev.java/learn/new-features/using-preview/

JEP 483: Ahead-of-time Compilation
https://openjdk.org/jeps/483

JEP 485: Stream Gatherers
https://openjdk.org/jeps/485

JEP 491: Synchronize Virtual Threads without Pinning
https://openjdk.org/jeps/491

JEP 494: Module Import Declarations (Second Preview)
https://openjdk.org/jeps/494

JEP 495: Simple Source Files and Instance Main Methods (Fourth Preview)
https://openjdk.org/jeps/495

The Foreign Function and Memory API
https://dev.java/learn/ffm/

The Foreign Function and Memory API will be finalised in JDK 22. This API helps you integrate native code within your Java program. 

Using this new API you can efficiently invoke code outside the JVM, safely access memory not managed by the JVM, call native libraries and process native data without the brittleness and danger of JNI.

Jorn Vernee, core contributor and maintainer of the FFM API, is Ana’s guest during this episode. Jorn explains what is the Foreign Memory Access API, its goals and the iterations that this API went through. Jorn also shares a few examples of Java libraries that already adopted the FFM API, the performance improvements they observed. He also explains how you can use this new API to integrate a native library within your own Java code.

Sequenced Collections, targeted for JDK 21, are a new collection type created to represent a sequence of elements with a defined encounter order.

Ana recorded this episode with Stuart Marks, the owner of JEP 431 about Sequenced Collections. Stuart discusses the essence of Sequenced Collection interfaces, what needs those address and how they fit within the existing Collections framework. He explains the design of Sequenced Collections, architectural decisions and particularities of the API. He also shares his view on how Sequenced Collections can inspire future Java platform developments.

Preview Features have been essential to the delivery of Java for the past 5 years, and Java 20 is no exception with second previews of both Virtual Threads and the Foreign Function & Memory API.

Chad discussing the importance of Preview Features with Alex Buckley, as well as an Informational JEP that added some further clarification for Preview Features with large surface areas.

Some show notes:

JDK 20 is out today: https://openjdk.org/projects/jdk/20/

JEP 12: Preview Features https://openjdk.org/jeps/12

A look ahead: https://openjdk.org/jeps/8300604

Helidon Níma is the first Java microservices framework built from the ground up on virtual threads.

David recorded this episode with Tomas Langer, the Helidon architect. Tomas discusses virtual threads from a framework developer point of view. He explains Níma, its architecture and how virtual threads fit in. He also shares his views on virtual threads and some behind the scenes details and how it all started.