Hello,
That the WO-Jars are closed source makes it really hard to move to the new
Java-Module-System. But I had a similar problem once and was able to solve it.
Maybe this can help here. But that requirement did not involve
My requirement was:
* I wanted to deploy a Java-Background-Service (a small WebApp with
REST-Interfaces) on Windows Desktop-Machines
* I wanted to have a single "exe" to start and the app should run. Using
the Java-Module-System it's possible to create an exe with the own code, all
dependencies and a stripped-down mini-Java-VM with just the required parts. So
you get an "exe" with around 20 MB which can run on any Windows without the
requirement that Java is installed
* This "exe" was distributed and started by Windows-Group-Policies (That
was the reason for this "one exe deployment")
I was able to do this with the following approach:
* Own Java-Maven-Project with my code. The project was built as
maven-"fat-jar" (so all class-files in one big jar)
* All project-dependencies were regular maven-dependencies. Most of the
dependencies were not in Java-Module-Format. And very important here: You are
just able to use Java-Module-Build when your code and ALL your dependencies are
in module-format!!
* I then provided an own "java-module-file" for alle my code AND all the
code of the project-dependencies (listing of all packages, ... Basically all
the stuff the Java-Module-System requires)
* My fat-jar-build throw this all together and builded a new jar which
contained my class-files, all dependency-class-files and a java-module-info and
therefore was a valid java-module-jar which I could bundle as an exe-file
So what to do with WebObjects? (Important: This is just an idea, I did not try
to do this!)
* Creating a new Project "WebObject-JavaModule"
* List all WebObjects-Jars as Maven-Dependencies
* Build-Target as "fat jar"
* Filter all classes which do not belong to WebObjects because they are
provided by the Java-VM or by other dependencies
* Filter all classes where ProjectWonder provides an improved/patched
version
* Write a java-module-file for all the remaining WebObjects-Class-Files
* Build this as "fat jar" and use this instead of the "old webobjects-jars"
in your projects or Wonder-Projects
* Now all Wonder-Projects could be updated to Java-Module-Format (As long
as all the other depencies of them are also in Module-Format)
But be aware of licence-restrictions: The WebObjects-Jars are distributed with
the WebObjects-Licence. The licence states that it is not allowed to decompile
the Jars and maybe this new "WebObjects-JavaModule" could be seen as derivative
work and could be legally not allowed to exists.
Best Regards,
Wolfgang
________________________________
Von: Aaron Rosenzweig via Webobjects-dev <webobjects-dev@lists.apple.com>
Gesendet: Samstag, 10. Dezember 2022 16:36
An: WebObjects-Dev List <webobjects-dev@lists.apple.com>
Betreff: Java 17? Half or Full?
This is both a topic for both pure NeXT/Apple WO as well as a WOnder.
Your WO deployments, are they on Java 17? Are they half or full Java 17? Please
chime in.
In our case, at present, we are developing and deploying on a Java 17 VM but
using Java 1.8 (version 8) compliance. I call this “Java 17 Half"
Definitions:
Java 17 Half -> Developing and deploying on Java 17 but using Java 1.8
compliance.
Java 17 Full -> Not only using a Java 17 VM but also targeting v17 compliance
and using JPMS (Java Package Management System) which was introduced with Java
9.
PHB -> “So I was golfing with my buddies and found out they are all using Java
17 *sealed* classes. This is so cool and will revolutionize our codebase. I
want you to start using it immediately. It was introduced with Java 17. I’m so
glad we are on a 17 VM.”
Me -> “Can’t do it”
PHB -> “Why not? You told me we went to Java 17 over a year ago.”
Me -> “We did and are on Java 17, but we compile for Java 1.8”
PHB -> “That’s no good. We need to be fully modern. We need to be able to use
new constructs as they emerge. Why are we compiling for Java 1.8 ? Is it a
problem with WOnder?”
Me -> “Because our core frameworks are closed source, from NeXT/Apple, our
hands are somewhat tied. That’s part of the problem. The other part is that
class loading changed dramatically with Java 9 onward and broke a lot of things
for many people. Because we leverage so much from Apple and WOnder, we pretty
much are stuck. Our frameworks are stuck in java 8 compliance and therefore so
are we”
Definitions:
Old Class loader -> Java 1.8 (version 8) and older.
New Class loader -> Java 9 and newer.
The new class loader tries to avoid “Jar Hell” but that’s something we actually
enjoyed about the old class loader. What Oracle saw as a weakness and sought to
fix, Sun saw as a strength. It’s causing us trouble right now with going Java
17 Full. Here’s an example.
Consider a jar named “animals_v1.jar” that has classes for birds and other
creatures. Imagine that there is also a newer “animals_v2.jar” Let me diagram
them below in pseudocode:
animals_v1.jar:
com.acme.Duck.speak()
animals_v2.jar:
com.acme.Duck.speak()
com.acme.Duck.hasFeathers()
Suppose you are using the old class loader and somehow had both jars in your
class path. It matters which jar is first because the first one wins when there
are multiple definitions in the class path for “com.acme.Duck”. You could have
a situation where things compile but at runtime there’s a failure because we
can’t ask “hasFeathers()” and it’s situations like these that Oracle considered
a design flaw or “Jar Hell.”
In our case, we considered this functionality of the old class loader a
strength. As long as we are careful, we can avoid the pitfalls but also do
clever patching of closed source Apple frameworks like so:
Apple java frameworks:
com.apple.NSArray
WOnder java frameworks:
com.apple.NSArray
By putting WOnder’s frameworks first in the class path, and being careful to
not remove needed functionality of NSArray, we can “overwrite” Apple's
implementation with an improved one while letting the rest of Apple’s code work
directly with our NSArray replacement. Unfortunately this breaks the new class
loader. It’s not allowed. Cannot have NSArray defined in more than one named
place. Even if we take WOnder out of the equation, we still have problems with
Apple’s JavaXML framework where it redefines W3C and DOM objects that java.xml
named module natively defines in modern Java.
If we want to compile for modern java on new VMs what can we do? I’m no expert,
so correct me if I’m wrong, but I’m trying to make sense of what our options
are. There is no easy path. There is no set of simple VM arguments or anything
magic that takes a small amount of effort. We’d have to do something like
TreasureBoat where we take ownership of the private libraries. We can’t
surgically replace a few objects in the private libraries anymore by class path
ordering and I don’t think Aspect-Oriented Programming nor Dependency Injection
can save us here either. We also now have conflicts in pure Apple libraries
with what is currently built-into Java.
How long are we ok using modern VMs but compiling for 1.8? “OK” meaning
functional but not allowed to use new Java language features.
2026 is when Amazon stops supporting 1.8 JVMs
2030 is when Oracle stops supporting 1.8 JVMs
I could not determine when javac compliance level support might be dropped for
Java 1.8 on modern VMs. That said, I guess it would be at least until 2030 when
Oracle no longer provides 1.8 VM support. It might last longer than that…
perhaps 2040. Hard to say. Lots of people are struggling with JPMS (Java
Modules) in similar situations as us. Such as this quote: "Your program might
even have a dep on some jar that was compiled under jdk4 and the author and
source are nowhere to be found (or went out of business a decade ago)... and
suddenly it breaks under java9. Things like that are largely what prevented
mass adoption of jdk9 immediately.”
We might be able to be creative by taking jars from multiple frameworks,
putting them in one modularized framework, and exposing something for a modern
java app. I’m not clear that would work but maybe. I think there are Apple
frameworks which conflict with named module java.xml which likely cannot be
worked around. This guy did something like this for his legacy frameworks (not
WO):
https://stackoverflow.com/questions/53245628/jdk9-automatic-modules-and-split-packages-dependencies
In closing, I don’t think it’s possible without rewriting closed-source Apple
libraries and also rewriting WOnder to target compliance level beyond 1.8. Is
there anyone building with compliance level beyond 1.8?
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