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openjdk
jdk
Java2019–2026
openjdk / jdk

jdk

JDK main-line development https://openjdk.org/projects/jdk

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93Distinct people
129Mentions
0Explicit recommenders
23.5KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

JDK main-line development https://openjdk.org/projects/jdk

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 10:01:16 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year129 dated mentions

Observed mentions: 2019-04-25 22:04:17 UTC to 2026-10-25 02:47:45 UTC.

01020302019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 7 mentions; 0 submissions, 7 comments20192020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 6 mentions; 0 submissions, 6 comments2021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 17 mentions; 1 submissions, 16 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 17 mentions; 0 submissions, 17 comments20222023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 28 mentions; 5 submissions, 23 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 22 mentions; 4 submissions, 18 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 12 mentions; 2 submissions, 10 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 20 mentions; 5 submissions, 15 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC707
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC606
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC17116
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC17017
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC28523
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC22418
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC12210
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC20515

What Hacker News says

17 sources
ptx·Sep 29, 2022
> Even if they stick with Java and try to learn jpackage they quickly realize they need Windows, and a Mac, and maybe Linux just to make packages that their friends can run at all And when they test it on Windows they'll realize that the launcher that jpackage creates does something weird on startup (possibly involving relaunching itself? [1]) that makes Windows display a busy cursor for a while after the program has launched, so they'll have to forget about jpackage and redo it all with something like Packr [2] and Wix# [3]... [1] https://github.com/openjdk/jdk/blob/fe45835f7cebfccd4544ae19... [2] https://github.com/libgdx/packr [3] https://github.com/oleg-shilo/wixsharp
In Paving the on-ramp to Java
amenghra·Sep 1, 2022
func string-compare-case-insensitive(x, y) { return lower(x) == lower(y) ? lower(x) == lower(y) : lower(x) == lower(y); } /s More seriously, if you want to learn about this, one place is to look at OpenJDK's sources. E.g. here: https://github.com/openjdk/jdk/blob/master/src/java.base/sha... which calls: https://github.com/openjdk/jdk/blob/17283cfe4c697e2118f19992... and https://github.com/openjdk/jdk/blob/17283cfe4c697e2118f19992...
In Falsehoods programmers believe about email
hyperman1·Jul 20, 2022
java.util.logging was braindead because it wanted to know the class and method doing the logging. If not provided, it threw and catched an exception and filtered the stack trace to detect its own caller. Throwing an exception was a very slow operation. I see they did some optimizations to do this work lazily if needed. But when log4j 1 was on its peak, that wasn't done, and using the built in logger was slow enough to have measurable impact . See https://github.com/openjdk/jdk/blob/6765f902505fbdd02f25b599... at the bottom.
In Log4j: The pain just keeps going
mike_hearn·May 3, 2022
There's no design conflict I'm aware of but you don't "just" implement virtual threads. The PR to do it in HotSpot is notoriously huge: https://github.com/openjdk/jdk/pull/8166 1,140 files, (+98,553 −9,862 LOC) and those lines of code are mostly horribly fiddly low level assembly/compiler hacking. This is partly why it took years of development. Most people don't realize this, especially because in the later stages of course many others contributed, but Loom is in some sense one man's journey. Before he worked at Oracle Ron Pressler spent years writing a library called Quasar which implemented fibers on top of the JVM using bytecode rewriting and some low level hackery with internal APIs. At some point he became available for hiring and Oracle brought him on board, as by that point he was not only an expert in fiber implementations but al
Read the rest
so the JVM. That was the genesis of Loom. Something I've learned from following the intricacies of VM development is that what we get is very much a result of hidden human stories as well as technical decisions. Features happen or don't happen on the basis of who was available to be hired at the time, as much as cold calculations of performance impacts. In turn that depends heavily on the vagaries of personal lives. The skills needed to do this work aren't that easy to find on the open market and training takes a long time. For other VM implementors to do this, and realistically only .NET has the sort of languages where it makes sense (JS doesn't), well, it'd take a long time even if they start today and there's no guarantee of success.
In JEP proposed to target JDK 19: 425: Virtual Threads (Preview)
xxs·Apr 25, 2022
There is a single OS call to put the current thread to sleep; I mentioned it much earlier - a single pthread_mutex_t per Thread NOT per lock Those are not any part of the developer capability to manage, aside starting the thread (and locking on it). The mutex is released with the thread, itself; Technically hotspot impl java does not ever releases them back to the OS but keeps a free-list. The thread is a lot larger OS resource as well. No new OS resources are exhausted by the OS b/c of the extra locking. >The claim that LockSupport, which is calling the OS is not a wrapper is bogus. Of course it does call the OS; it happens on the dormant part (w/o an OS call it'd a busy spin), or if a thread needs to be awaken. I said not a 'thin' wrapper. All the locking and queueing mechanism is outside the OS. The major distinction is there is onl
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y a single OS primitive per Thread NOT per lock. (Edit: now I see I have spelled thin as 'thing' which is a definite mistake on my part) /* * This is the platform-specific implementation underpinning * the ParkEvent class, which itself underpins Java-level monitor * operations. See park.hpp for details. * These event objects are type-stable and immortal - we never delete them. * Events are associated with a thread for the lifetime of the thread. */ https://github.com/openjdk/jdk/blob/c4c76e2f34f7e709f8b3c960... // ParkEvents are type-stable and immortal. // // Lifecycle: Once a ParkEvent is associated with a thread that ParkEvent remains // associated with the thread for the thread's entire lifetime - the relationship is // stable. A thread will be associated at most one ParkEvent. When the thread // expires, the ParkEvent moves to the EventFreeList. https://github.com/openjdk/jdk/blob/739769c8fc4b496f08a92225... Edit: My point has always been that locks/monitors/semaphores/etc. dont need any special care in a GC-setup as they can be implemented purely in the language itself, and without special care to release them, and manage them similar to file descriptors. The need to block (become dormant) obviously requires OS calls and support but that part doesn't have to scale with the amount of locks/semaphores/latches/etc. created.
In Chris Lattner on garbage collection vs. Automatic Reference Counting (2017)
xxs·Apr 24, 2022
>If you get semaphores from create_sem() you will need to give them back... I don't quite get the continued argument - the created locks in the user space have 'zero' extra dependency on the kernel. In a GC setup they would be an object no different than a mere string (likely less memory as well). They can be GC'd at any time as long as there are no references to them. If you wish to see an example: java.util.concurrent package. ReentrantLock[0] is a classic lock, and there is even a Semaphore in the same package (technically not in the very same). Originated in 2004 with JMM and the availability of CAS. You can create as many as you choose - no kernel mode switch would occur. For the record I do no object that proper resource managed is needed - incl. sqldatabase close. The latter does use a file descriptor any time you establish a conne
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ction. However, locks need no special support from the kernel. Also in GC'd setup file descriptors would be GC'd in pre (or post) morterm via some finalization mechanism, however relying on the GC to perform resource management is a terrible practice. [0]: https://github.com/openjdk/jdk/blob/master/src/java.base/sha...
In Chris Lattner on garbage collection vs. Automatic Reference Counting (2017)

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