“Draw the Rest of the Owl: Leyden in Production and the Infrastructure Needed to Get It There.”
Learn how Netflix used Project Leyden to improve startup time of critical services and the software and SDLC they built to make that happen.
Presented by Martin Chalupa (Netflix) and Ian Brown (Netflix) at JavaOne 2026 (CA, March 2026).
Make sure to check the JavaOne 2026 playlist.
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The OpenJDK Quality Group is promoting the testing of FOSS projects with OpenJDK builds as a way to improve the overall quality of the release. This heads-up is part of a Quality Outreach update sent to the projects involved. To learn more about the program and how to join, please check the Quality Outreach wiki page.
JSON thread dumps generated by com.sun.management.HotSpotDiagnosticMXBean.dumpThreads and the jcmd Thread.dump_to_file command now write thread identifiers, thread counts, and the process identifier as JSON numbers instead of strings.
For example, when using a command like jcmd <PID> Thread.dump_to_file -format=json threads.json to write thread stack traces to a file in JSON format, the output would look like in the snippet below.
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]]>{
"threadDump": {
"formatVersion": 2,
"processId": 36340,
"time": "2026-05-15T12:43:21.601545Z",
"runtimeVersion": "27-ea+22-2010",
"threadContainers": [
{
"container": "<root>",
"parent": null,
"owner": null,
"threads": [
{
"tid": 3,
"time": "2026-05-15T12:43:21.604046Z",
"name": "main",
"state": "TIMED_WAITING",
"stack": [
"java.base\/java.lang.Thread.sleepNanos0(Native Method)",
"java.base\/java.lang.Thread.sleepNanos(Thread.java:562)",
"java.base\/java.lang.Thread.sleep(Thread.java:593)",
"HelloThreads.main(HelloThreads.java:4)",
"java.base\/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)",
"java.base\/java.lang.reflect.Method.invoke(Method.java:583)",
"jdk.compiler\/com.sun.tools.javac.launcher.SourceLauncher.execute(SourceLauncher.java:260)",
"jdk.compiler\/com.sun.tools.javac.launcher.SourceLauncher.run(SourceLauncher.java:138)",
"jdk.compiler\/com.sun.tools.javac.launcher.SourceLauncher.main(SourceLauncher.java:76)"
]
}
],
"threadCount": 7
}
....
]
}
}
This change of format also introduces versioning through "formatVersion": 2 member, while metadata fields such as processId, tid, and threadCount are serialized as JSON numeric values rather than JSON string types.
We encourage you to download the JDK 27 early-access builds and test any tools, scripts, tests, or applications that parse JSON thread dumps. If needed, update them to handle numeric values for thread identifiers, thread counts, and the process identifier, and use the new formatVersion field to detect and handle future thread dump format changes.
Since JavaOne 2025, JDK 25 was released, the latest version with long-term support. But Java never stands still; it’s already time to ship JDK 26. This talk summarizes the most important changes between Java 21 and 25:
main to launching multisource-file programs… before taking a closer look at the newest release, including its preview features:
There are plenty of features in the language, API, and runtime to discuss; whether new, improved, or finalized. Let’s go over them.
Make sure to check the JavaOne 2026 playlist.
]]>Caching is a first-class architectural concern in agentic systems. This talk breaks down how Java applications can layer internal, distributed, and semantic caches. We’ll explore in-process caching with Caffeine for ultra-low-latency access, distributed caching with Redisson and Valkey for shared cache and semantic caching using Vector Similarity Search to reduce latency and cost while scaling LLM access.
Make sure to check the JavaOne 2026 playlist.
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The OpenJDK Quality Group is promoting the testing of FOSS projects with OpenJDK builds as a way to improve the overall quality of the release. This heads-up is part of a Quality Outreach update sent to the projects involved. To learn more about the program, and how-to join, please check here.
JEP 527 has been integrated in JDK 27 early-access builds, bringing hybrid post-quantum key exchange to TLS 1.3. This improves Java’s TLS implementation by combining traditional elliptic-curve key algorithms with quantum-resistant ML-KEM, helping protect against future harvest-now, decrypt-later threats.
Java applications that use the standard javax.net.ssl APIs can benefit by default, without code changes, as long as they do not override the TLS named groups.
By default, JDK 27 enables X25519MLKEM768 alongside existing classical key exchange algorithms, so TLS clients offer both a hybrid X25519MLKEM768 key share and a traditional x25519 key share.
JDK 27 adds three hybrid key exchange options through the SunJSSE provider:
X25519MLKEM768 is a hybrid scheme combining ECDHE with X25519 and ML-KEM-768.SecP256r1MLKEM768 is a hybrid scheme combining ECDHE using the secp256r1 curve with ML-KEM-768.SecP384r1MLKEM1024 is a hybrid scheme combining ECDHE using the secp384r1 curve with ML-KEM-1024.You can customize the enabled groups either with the jdk.tls.namedGroups system property or programmatically via SSLParameters::setNamedGroups:
SSLSocket tlsSocket = (SSLSocket) SSLContext.getDefault()
.getSocketFactory()
.createSocket();
SSLParameters params = tlsSocket.getSSLParameters();
params.setNamedGroups(new String[] {
"SecP384r1MLKEM1024",
"X25519MLKEM768",
"secp384r1",
"x25519"
});
tlsSocket.setSSLParameters(params);
As this implementation is still new, we encourage you to download the JDK 27 early-access builds, try this feature, and share your feedback through the security-dev OpenJDK mailing list (registration required).
This session highlights the progress of JEP 528, which brings core dump and minidump support to jcmd. The jcmd tool is widely used for monitoring and troubleshooting live HotSpot JVMs. With JEP 528, jcmd will also be able to diagnose crashed JVMs, creating a more consistent troubleshooting experience across both live and post-mortem environments.
Join us for a deep dive into the future of JVM crash analysis and post-mortem diagnostics.
Make sure to check the JavaOne 2026 playlist.
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