Upgrading from Java 17 to 21 #RoadTo21

Java 21 is chock-full of great features and if you’re coming all the way from 17, there’s a plethora of additions to use and get used to, but it’s all for naught if you can’t actually update. In this #RoadTo21 episode, we discuss all you need to know to update from Java 17 to 21: API changes that may require you to update your code (like the introduction of sequenced collections or bug fixes in Double/Float::toString and IdentityHashMap), ongoing deprecations (threading, security manager, finalization, and more) and changes in networking (like earlier URL validation and HTTP timeouts), encoding (UTF-8 by default and changes in date/time/unit formatting), the runtime (like removed options class loading), and tooling (like new warnings). We’ll also go beyond the nitty-gritty details and see the bigger picture of how to best prepare and execute your Java and 3rd party updates by talking about , release notes, Quality Outrach, and much more. ~~~ Chapters & Links ~~~ 0:00 Intro 1:40 API changes sequenced collections: XSL transformations: #JDK-8290347 Double/Float::toString: IdentityHashMap: #JDK-8178355 3:44 Ongoing deprecations Inside Java Newscast: Thread degradation: ThreadGroup degradation: #JDK-8284161 security manager - Inside Java Newscast #5: security manager - heads-up: security manager - JEP 411: finalization - Inside Java NEwscast #15: finalization - JEP 421: dynamic agent loading: 6:52 The more you know Inside Java: Java 20 release notes: 8:56 Networking network interface names: URL validation: stricter JNDI providers: #JDK-8278972 HTTP client timeouts: #JDK-8297030, #JDK-8288717 10:25 Encoding UTF-8 encoding - heads-up: UTF-8 encoding - article: UTF-8 encoding - JEP 400: CLDR v42: 13:52 Quality Outreach website: Outreach on : 16:31 Runtime biased locking: #JDK-8256425 G1 changes: #JDK-8137022, #JDK-8017163 ClassName/: parallel-capable class loaders: Metal - heads-up: Metal - construction: 19:02 JDK Tools serialization warning: JAR index: jlink --compress: jpackage --app-image: 20:31 3rd party updates 21:48 How to update OpenJDK Archive: (Don’t run outdated versions in production!) 23:39 RoadTo21 previews ~~~ ~~~ Tags: #Java21 #Update #Java #OpenJDK #InsideJava