Project Jigsaw: Complete
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Project Jigsaw: Complete
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Re: Project Jigsaw: Complete
#2Does it have any positive impact on startup time for simple programs if you are not loading large chunks of the JVM?
Re: Project Jigsaw: Complete
#3I think it's going to take me a while to learn about the module system in Java 9, I'm probably going to bank on watching other projects do it first to see if any best practises emerge as developers get used to the new way of working.
One thing I will say though is Java 9 has had a definite improvement on Java applications that run on my Raspberry Pi 3, I think because this got included http://openjdk.java.net/jeps/297
One application used to take 55s to start up, now it takes around 15s!
Re: Project Jigsaw: Complete
#4I don't follow Java too closely and the world "module" is so hopelessly generic that I had a hard time understanding what the article was talking about. It links to this document [1] though, which is a long read, but does an excellent job of describing of describing all the ins and outs of the module system.
(tl;dr Packages can now declare themselves as modules instead of simple namespaces, and they get to choose exactly what they export and what other modules they require. Projects can now resolve their types from within modules with a module path instead of on a per-type basis from the class path. It's a huge step forward for Java modularity and dependency management.)
I have a hard time being too impressed because more modern languages are doing this out of the gates and with far fewer hacks and more out-of-the-box tooling (e.g. Rust), but acknowledge just how monumental of an effort it was to design the new system and then build it into Java's core in a way that's mostly backwards-compatible. Java's going to be around for a long time, and this is a big long-term gain for the ecosystem.
I'd really love to see languages like Ruby tackle this next. It's sorely needed.
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Re: Project Jigsaw: Complete
#5I don't follow Java too closely and the world "module" is so hopelessly generic that I had a hard time understanding what the article was talking about. It links to this document [1] though, which is a long read, but does an excellent job of describing of describing all the ins and outs of the module system. (tl;dr Packages can now declare themselves as modules instead of simple namespaces, and they get to choose exa…
> I have a hard time being too impressed because more modern languages are doing this out of the gates and with far fewer hacks
Well of course - it's easier to build something like this into a clean-slate language isn't it? It's harder to build it into an existing language and VM spec with an incomprehensibly large volume of existing code to be compatible with. It's backwards to say it's not impressive because someone else with zero constraints to work with also managed it.
Re: Project Jigsaw: Complete
#6Does it have any positive impact on startup time for simple programs if you are not loading large chunks of the JVM?
yes.
especially since in the future you can actually compile modules as libraries and aot load them.
at the moment this is experimental and should probably only work for java.base
Re: Project Jigsaw: Complete
#7I don't follow Java too closely and the world "module" is so hopelessly generic that I had a hard time understanding what the article was talking about. It links to this document [1] though, which is a long read, but does an excellent job of describing of describing all the ins and outs of the module system. (tl;dr Packages can now declare themselves as modules instead of simple namespaces, and they get to choose exa…
> I have a hard time being too impressed because more modern languages are doing this out of the gates and with far fewer hacks Well of course - it's easier to build something like this into a clean-slate language isn't it? It's harder to build it into an existing language and VM spec with an incomprehensibly large volume of existing code to be compatible with. It's backwards to say it's not impressive because someon…
> Well of course - it's easier to build something like this into a clean-slate language isn't it? It's harder to build it into an existing language and VM spec with an incomprehensibly large volume of existing code to be compatible with. It's bizarre to say it's not impressive because someone else with zero constraints to work with also managed it.
I hope my original comment was relatively clear on this, but sure, it's a big accomplishment and will be a quantum leap for the ecosystem. However, given that languages elsewhere have had better systems for quite some time now, it's not like they're advancing the state of the art in dependency management.
But again, it wasn't an easy thing to do (a very hard thing even) and everyone involved deserves major felicitation.
Re: Project Jigsaw: Complete
#8I don't follow Java too closely and the world "module" is so hopelessly generic that I had a hard time understanding what the article was talking about. It links to this document [1] though, which is a long read, but does an excellent job of describing of describing all the ins and outs of the module system. (tl;dr Packages can now declare themselves as modules instead of simple namespaces, and they get to choose exa…
> I have a hard time being too impressed because more modern languages are doing this out of the gates and with far fewer hacks Well of course - it's easier to build something like this into a clean-slate language isn't it? It's harder to build it into an existing language and VM spec with an incomprehensibly large volume of existing code to be compatible with. It's backwards to say it's not impressive because someon…
Can someone with an idea about this post other languages that actually attempt to modulerize it's own API? I'm not aware of any.
Re: Project Jigsaw: Complete
#9Jigsaw was what held up the Java 9 released, due to some members rejecting the proposal. It was changed and revoted upon, but it's hard to follow what was modified to make it acceptable.
Is there anywhere the design goals and constraints for modules are? I'd really like to know how they ended up in their current form.
Re: Project Jigsaw: Complete
#10Jigsaw was what held up the Java 9 released, due to some members rejecting the proposal. It was changed and revoted upon, but it's hard to follow what was modified to make it acceptable. Is there anywhere the design goals and constraints for modules are? I'd really like to know how they ended up in their current form.
> Jigsaw was what held up the Java 9 released, due to some members rejecting the proposal.
That was only a few weeks. If you check the official release schedule http://openjdk.java.net/projects/jdk9/ Jigsaw was supposed to be feature complete a year before that vote happened. Jigsaw was simply not close to ready when it was merged to master. And yes, Oracle still claims it hit every milestone on that schedule.
> It was changed and revoted upon, but it's hard to follow what was modified to make it acceptable.
http://openjdk.java.net/projects/jigsaw/spec/minutes/2017-05...
http://openjdk.java.net/projects/jigsaw/spec/minutes/2017-05...
http://openjdk.java.net/projects/jigsaw/spec/minutes/2017-05...
Not much really. Basically Oracle called their bluff. At that point is was really too late as Jigsaw was already merged to master and more or less touched every part of the JDK.
> Is there anywhere the design goals and constraints for modules are? I'd really like to know how they ended up in their current form.
Not really, it was really just Oracle making things up as they went. For the past ten years Mark Reinhold would give talks at Java conferences what the module system comping in the next Java version was supposed to do and every year the content was different. For example they have no good explanation while they mashed the module declaration into a .class file, basically everybody except Oracle thinks it's a bad idea but the just went with it anyway. They claim "reliable configuration" as a goal but without versioning that's meaningless.