Inside Java

G1 is Java's default garbage collector in most environments, and its throughput has been considerably improved in JDK 26 by streamlining its write barriers. This conversation explores the background of that change and dives deep into regions, write barriers, concurrent marking, card tables, and how all that impacts throughput before eventually getting to the improvements made in Java 26, which lay further groundwork to G1 becoming the one and only default collector across _all_ environments.
In this "Ask the Architect" episode of the Inside Java Podcast, recorded during JavaOne 2026, Nicolai Parlog talks to Stefan Johansson, Hotspot Garbage Collection engineer at Oracle.
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The Java tool jcmd ("j command") sends diagnostic commands to the JVM, which will react by supplying the desired information: from finalizer queues to heap and thread dumps, from GC insights to virtual thread scheduler statistics. At the moment, this requires a running JVM, but once candidate JEP 528 is adopted, a lot of that information can be seamlessly extracted from a crashed JVM's core dump, allowing easy post-mortem analysis.

Carrier classes are Project Amber's current idea to extend some of records' benefits to regular classes. Probably the most important among them is deconstruction, which would allow classes to participate in pattern matching and reconstruction. In recent weeks, there have been two mails to the Amber mailing list that describe that idea, and in this episode we discuss them both as well as the evolution between them. We also hear why syntax discussions often provide negative value and get a sneak peak at what will likely be the next Project Amber language feature.
Just ahead of the JavaOne speakers dinner, Nicolai Parlog sits down with Brian Goetz, Java Language Architect in Oracle's Java Platform Group, for this "Ask the Architect" episode of the Inside Java Podcast.

Java 26 is getting all packaged up to be shipped worldwide! As with every release of the JDK there are a number of new features, improvements, changes in behavior, and more developers should be aware of before upgrading. In this episode of the Inside Java Newscast we will review all the noteworthy changes coming in Java 26 that will impact developers.

Java's checked exceptions are both an integral part of the language and one of its most contested features. Whether their introduction was a mistake and whether they should all be turned unchecked are frequently discussed topics but since the former is not overly relevant and the latter unlikely, this conversation isn't moving Java forward. Instead, let's talk about specific issues with checked exceptions and what could be done about them - from (entirely speculative) language changes to (marginally realistic) JDK/library evolution to stylistic changes.