The general guidance is always use the last LTS release unless there is a specific feature in the non LTS releases that you can’t wait for. So any new development should target 17 at this point.
Unless you want serious long term pain then you shouldn’t be more than one LTS release behind. So if you are not running on JDK 11 or later you should be strongly thinking about upgrading.
Currently upgrading a ~1M SLoC Java enterprise app (with regular Spring, Jetty in there, scheduled processes, PrimeFaces for web UI, REST API services, SOAP services, the whole shebang) from Java 8 to Java 11 (since 17 wasn't out when that change was approved) and it's largely proving to be a pain. Since the version of Spring is ancient and changes over to Spring Boot were also approved, now have to rewrite parts of it and also get rid of the XML configuration and other old approaches which are simply no longer compatible with this upgraded tech stack. It feels like something that perhaps a team should do, instead of one dev over a month or so, but scope creep and estimates for something like that are nigh impossible, so we'll see.
My point is that migrating to new releases isn't always trivial, especially the more complicated and complex a project gets. If i knew that i'll run if compiled successfully, then it wouldn't be too bad, but with the amount of reflection, dynamic class loading etc. that frameworks like Spring favor, my workflow to date has been fixing a bug, building and running, something else breaking, fixing that bug, building and running, something else breaking, realizing that i cannot fix this because upgrades to the logic would be inherently "lossy" due to a mismatch of what the new framework versions provide, making it so that breakages that aren't covered by tests will also be created and so on ad infinitum.
Sometimes it makes me wonder why JDK 9 onward just didn't have a compatibility module: "Here, install this to have all of the old Java classes that were removed from the standard library after JDK 8 and retain that old functionality for software projects that would otherwise be stuck in development hell short of a full rewrite." Or something like that for Spring Boot, that lets you use web.xml instead of having to use hacks to load its contents and register all of the servlets, with half of them not working anyways, because some class names were changed along the way.
Software doesn't always age beautifully.
Furthermore, it feels like new runtime and package versions are made in ways that accidentally break backwards compatibility with no clear ways to avoid this.
I got stuck in this conundrum at my previous gig as well, and think reached a very different conclusion than you. In short, while I’m skeptical of some of the degree of churn across modern software development as a whole, I’m not sure that this is actually an issue with the Java ecosystem, which has been, and I think continues to be, way more sensitive to backwards compatibility than almost any other ecosystem.
In some ways, this is just a consequence of a kind of evolutionary leap forward for many applications. We don’t deploy our WARs into application servers anymore, we try to pack a fat JAR, or maybe even a statically linked runtime, into a container. We rebuild the whole world on CI all the time. I mean, Java 8 has issues just respecting cgroup limits, which many a despondent ops engineer has discovered.
I think there’s still room for the 1M SLoC monolith even in this new world, but there are real benefits on the horizon for upgrading to Java 17 and beyond. We’ve reached a point where it’s just more expensive not to make upgrades a regular part of you development cycle. And, no one is stopping you from just staying on 1.8. I mean, I’m sure there are still decaying enterprises stranded on 1.3.
Personally, i'd never let a single monolith grow that far. Having a problem component or two that could be left on JDK 8 until they die and are rewritten (which would actually be possible with systems that have clearly defined boundaries and smaller scope), while migrating everything else.
Sadly, i don't get that choice, nor do i get the choice to make the judgement call to leave the monolith on JDK 8 in the name of stability. But hey, at least i'm paid a bit of money for it, so i have some motivation to work on all of it to the best of my abilities, learn a bit more about the JDK internals, have a word or two to tell others about my experience before i inevitably burn out from the churn.
Personally, i do still think that Java is pretty good when it comes to stability and backwards and forwards compatibility, especially since tooling like Maven is actually pretty good when compared to the alternatives (well, the parent POM functionality is confusing sometimes, but oh well, it has its use cases). That said, JDK 8 to newer releases was indeed a generational shift (probably one for the better) and you see similar things with Spring Boot 1.5 to Spring Boot 2.X, those breaking releases are inevitable.
I only wish that the things blocking people from writing more modular systems would disappear over time, so that huge monoliths that are incredibly hard to work with wouldn't be such an issue. I'm not necessarily advocating for microservices here, since people tend to go straight from one ditch into the opposite one (multiple services per person, nightmarish service mesh, needlessly large % of the code being for shuffling data around, suddenly building a distributed system even within a single domain), but at the very least it would be really nice to have someone look at it and say: "Hey, this PDF generation logic looks really brittle and perhaps should be a service of its own." or maybe: "Oh, hey, we're serving our RESTful API calls and front end resources from the same application, maybe we should have a separate front end app, served through a regular web server?"
Then again, if nothing else, i always have the choice to choose where i'm employed, even though i don't feel like letting my coworkers down at the moment either.
In general you are right that the Java ecosystem is highly backwards compatible, but 9 is a bit of an exception. The module system breaks a lot more stuff than usual, and is the reason a lot of legacy is stuck on 8.
Isn't your problem above essentially with Spring rather than the new JDK? Presumably Spring is using internal APIs that have changed in JDK11.
And yes, the reflection and dynamic behaviour in Spring are not type safe (i.e. runtime failures). Spring XML is a manifestation of "Greenspun's tenth rule" - it gives people the flexibility of Lisp/Python by unsurprisingly removing static type safety - not a trade-off that many will agree with. You should tell management that your job had been made harder by the choices made by the original architects of the system (who I assume are long gone),
It sounds like the problem is the scope creep. Do the JDK upgrade or the spring boot migration first. Yes it is tempting to do both at once but you are adding a lot of risk.
Agreed! Sadly, it wasn't my choice to make. Then again, if it's an older version of Spring, chances are that a lot of changes would be needed regardless.
Can you give a specific technical problem with updating from 8 to 11? Everyone says it's hard - nobody's ever able to give a practical example of a problem.
Oh, I have a fun one. The company I work at leverages Nashorn for running some user-customizable scripts and when upgrading from 8 to 11 we found out that Nashorn changed the way they express numbers under the hood. Basically, every number is either an integer or a float and it used to be that every number was a long or a float.
This silently broke a bunch of scripts and callbacks because of class cast exceptions and such. The solution was to rewrite the scripts in such a way to import the Java Long class and use that directly to express large integers.
The most important breaking issues I've found were not necessarily in our code base, but in dependencies. Libraries that include libraries that include libraries, all doing their own thing, a lot of the time involving some pretty scary reflection stuff for some unexplained reason. Blindly upgrading libraries only gets you so far, sometimes a dependency gets abandoned and you need to find a replacement and rewrite your code to call the APIs in the right manner to be backwards compatible enough.
Because Java, particularly pre-8 Java, sucks so bad if you try to actually write your whole application in it.
(I always found this really frustrating when making the argument for Scala. Yes, Scala-the-language is more complex than Java-the-language. But it's not more complex than the pile of reflection magic that anyone who tries to write a nontrivial system in Java actually ends up using).
From what I've seen: to add automagic functionality, syntactic sugar and wrapper methods for libraries. The JVM/Java language doesn't seem to have the tooling necessary to accomplish this natively, so it's the only reliable way to do it without relying on annotation processors having properly run (which still require some reflection magic, depending on the use case).
It is the dependencies. We bit the bullet and cut over (most) everything to Java 11 last year. Things that were removed from the JDK into new dependencies were the easier bits to sort - JAXB, some old Sun classes, and Java EE bits. All that was less than a week to sort. The real work were with the older 3rd party libraries not making the jump. You end up with turtles all the way down in some cases. Those took a serious amount of hunting for replacement. Mind you, the code was almost always something that had no budget or appetite for maintenance, so the moment you had to jump to a new package/API... folks often gave up.
All that said - for the 'normal' Springboot applications, we saw almost a 25% performance jump for the same code - updated libraries - running on K8. Java 11 was a substantial performance improvement. The jump for us to Java 17 will happen this winter, and looks to be a non-issue so far.
When you stumble upon something like that, at best you can import a Maven dependency with a version that has what you need, at worst you need to rewrite the code to use another library or set of libraries.
If you have any low level logic like custom class loaders written against older JDK versions (think before 8), then they'll be forwards compatible until 8 for the most part, but will break afterwards. Coincidentally, reading code that deals with low level logic is also not easy to do, especially if it's not commented well.
If you rely upon reflection, or use advanced language features (like the JasperReports framework for generating PDFs, which also has a build step for building the reports), in some cases things might compile but not work at runtime due to class mismatches.
Many frameworks need new major versions to support newer releases than JDK 8, for example Spring Boot 1.5 needs to be upgraded, so you're also dealing with all the changes that are encapsulated by your dependencies. In another project that i also migrated, needed to rewrite a lot of web initialization code for Spring Boot 2.X.
Not only that, but with those framework changes, certain things can break in the actual environments. For example, if you package your app as a far .jar, then you'll no longer be able to serve JSP files out of it. It makes no sense, but packaging it as a .war which can be executed with "java -jar your-app.war" will work for some reason.
I some other libraries, method names remain the same, but signatures change, or sometimes things just get deprecated and removed - you have to deal with all of that, which is especially unfun in code that isn't commented but that the business depends on to work correctly. Throw in external factors such as insufficient coverage of tests and you're in for an interesting time. I'm not saying that it's a type of environment that should be condoned, but it's the objective reality in many software projects.
Oh and i hope that you're also okay with updating all of your app servers (like Tomcat) or JDK installs on the server as well, especially if you depend on some of the Tomcat libraries to be provided and for your frameworks/libraries that depend on them being present at runtime to accept those new versions effortlessly. It all feels very brittle at times.
This is especially a nightmare if your servers were configured manually - personally i'm introducing Ansible and containers to at least isolate the damage of Ops rot, but it's been an uphill battle since day 1.
Here's an exceedingly stupid one: sometimes there are checks in code to make sure that you're using the right version of JDK (or even the Oracle JDK), which get confused with the larger versions. It's easy to fix when it's your code, but really annoying when it's external tools - personal nitpick.
Addendum: here's something that i expected to break, but didn't. We use myBatis as an ORM. It has XML mapper files that define how to map entities and construct queries against the DB based on that. Also, it uses Java interfaces and dynamically calls the underlying XML code as necessary. So essentially you have an interface, which has a corresponding XML file in which you have quasi-Java code (e.g. checking what parameters are passed in to the query) that's used alongside a number of tags to dynamically build SQL queries. Here's an example: https://mybatis.org/mybatis-3/dynamic-sql.html
Instead of something breaking in myBatis, what broke actually was Hibernate in the newer versions of Spring. Oh, and Flyway for DB migrations simply used to work with a particular Oracle DB version as well.
I hope you move to spring voot first vefore upgrading to JDK11, or vice versa.
I'm in the middle of a migration to 11 and my general approach has been to get it compiling on 11 while targeting 8 with (--release 8). That seems to catch a great many things that would otherwise fail. The hardest part thus far was figuring out the appropriate libs to replace Java 8 ee stuff, mostly wrt soap and xml. I'm hoping moving to 11 goes smoothly but we'll see. I'm hoping to have the artifacts to a point where they can run on either 8 or 11 without issues.
JDK 8 -> 9 migration was painful, but all other upgrades should be painless (well, maybe the 16-17, but I assume that most libraries will be fixed by the time you upgrade - either add `add-opens` instructions or use appropriate new classes from JDK).
We had that about a year ago in our product as well, though from Java 7 to Java 11. That JDK 9+ hump was definitely bad, but since then each incremental JDK has been smooth. The idea of using "the latest JDK" is fairly modern in the Java world, so people are still getting used to it. I'd say it's good now though, with perhaps 16 -> 17 being a minor hump since things that were deprecated but allowed in 9+ are now removed.
I think this is one of the few benefits of micro service architectures. You end up with much smaller pieces to migrate over. And if the service is well defined and you have ample logging for endpoints you actually could re-write it.
Mind you; you usually end up with the services all in different states of node/jdk/etc versioning(at least the companies I worked at).
Aa somebody who has had to do a Spring upgrade in the past, from 2.x to 4.x, I suggest you do Spring first, then the JDK after. Spring still supports 8 well after it starts supporting 11. Once you reach a certain version of Spring, upgrading the JDK is as simple as changing a 1.8 into an 11.
I don't know PrimeFaces, but I have worked with JSP, which does have a flag to set the compiler version (in case you were ever thinking about putting java lambda's in JSP files, which is possible but not recommended due to mixing code).
The hardest part of upgrading the JDK is going from 8 to 9. After 9 it is much more forgivable. As for Spring, major versions are a pain, as is Hibernate. The other parts of Spring are generally well upgradable if you read the Spring changelogs.
Upgrading Spring and especially major Boot versions is usually much more work than bumping Java version.
Boot change how it does config and such which .. can be confusing.
There is more to this now tho, because even their topline recommendation misses the fact that Temurin (anagram of runtime) only provides a small subset of tested builds you need.
They are in there but easy to miss - Bellsoft actually have builds for both jdks and jres for more than mainstream x86_64. Termurin dont even have jres anymore (last time I checked)
JREs have basically been replaced with building custom executables via jlink. It basically includes a barebones JVM with only the modules that you need. You no longer have to either distribute or ask your users to download a JRE that includes the kitchen sink, you instead use jlink to create a custom distribution that only includes the modules that your code actually uses. For example, if your application does not use Swing, jlink won't include it.
If you are distributing software based on java a 40mb jre in place of a 400mb jdk is surely preferred.
You can build them yourself for each OS you target with jlink, or you can just grab the latest built and tested one from e.g. Bellsoft - but not Adoptium or Oracle.
Java has been "breaking changes" between releases to make python blush for a few years now, 17 finally looks like a worthy migration from 8.
JRE is like 44MB, JDK is 190MB. Difference is not 400 MB. And you get jshell, javac all the nice tools that I missed when some wise guys in distro or corp decided JRE is enough.
Officially at least it seems that there are no post Java 8 JREs (or maybe Java 11 - I don't remember exactly) which is a shame. I know I can do it myself but having a small off the shelf runtime sure was convenient.
there is no "officially" anymore, java has gone open source with distributors kinda like linux distributions.
adoptium isn't the best distribution if you want to run on more than win/lin/mac x86_64.
Why should I stick to LTS?
All other versions aren't in any way less tested, you should always stick to the newest released JDK version, be it LTS or not, this way you get all the benefits (language features, performance gains) and security ones (security fixes always first land in the newest version, and are backported to the older ones).
Upgrades now are pretty straightforward if you are past JKD 9 - with JDK 16-17 being a bit tricky, but less than JDK 9.
Maybe, but those I use didn have any trouble with any java release.
Using so called LTS without paying for it is in no way different from using latest. You get similarly tested software and no one to call if you need a security fix asap.
> All other versions aren't in any way less tested
That depends. If most people follow the advice of "sticking to LTS", these versions will have way more users, and thus will be more "battle-tested", as in tested in production.
Support for vulnerability patches, stability, and so on. You can automatically update and maybe that goes well and maybe problems are caught in testing. Regardless those events and changes have over time have increased costs. LTS should mean lower costs both through increased support focus, increased population of active users, and reduced forced change.
After 6 months you move to the next release, just like most people do with libraries, JDK is just another library, no need to worry about upgrading, just do normal regression like with upgrades of other libs. There are no major releases of JDK, all current ones are minor ones - just like in case of JDK 8 you got new features in minor releases (e.g. change in changing of toString, added classes in standard library - no one was worried about that then)
OpenJDK serves as the upstream for many Java distributions (maybe all?) and it has no notion of LTS. LTS is just something to which vendors commit as outlined at https://openjdk.java.net/projects/jdk/17/ : “JDK 17 will be a long-term support (LTS) release from most vendors.”.
In other words, OpenJDK does not follow any LTS/non-LTS release cycle. Hence there is nothing special about Java 17 vs 16 when it comes to stability.
Even preview features are production ready (I used them in production) . Just the api might change or it could be removed, but quality wise it is as good as it can be.
There haven't been any notable language features added since java 9 besides some basic syntax sugar (which is already covered by stuff like lombok anyway).
For features and performance you might as well just target .NET 6. It has things that have been perpetually 'too hard to implement' (read: oracle doesn't want to pay their engineers to impl it and will sue you if you do it yourself) like value types, generics without type erasure, no checked exceptions, etc. and with .NET 6 performance is better than OpenJDK across the board.
Yes - .NET 5 and 6 both have runtimes and SDKs available for Mac and Linux. At least in my opinion, Linux is the preferred deployment platform for it now unless you have a specific (usually older) library that only works on Windows.
> .NET 5 finally delivered Linux support but only eleven months ago
The previous versions in this stream (.NET Core 2.1, .NET Core 3.0 and 3.1) also run fine on Linux. For web server / API server workloads, it's been stable for a lot longer than 11 months, and people do indeed "bet the farm" or "run the business" on it, quite happily.
Technically, this starts with .NET core 2.1 on 2018-05-30. The prior version, 2.0, released on 2017-08-14, wasn't _quite_ there yet although some people were happy with it for production use.
.NET has been on Linux for years now. And my company is using it in production on Kubernetes (Linux/Debian). Its crazy how dependable and fast it is. Startup times are amazing and its only getting better each year. We're looking to upgrade to .NET 6 in production by January.
Have you even seen the benchmarks compared to Java and other languages?
I can also confirm that I’ve been using .NET on non Windows OSes for years and it works really well. However the Benchmarks are rigged. The code they wrote for that one benchmark for in the top is a complete cheat. Check out the source and compare it with the other ones from the top 10. .NET is fast but Java is truthfully still faster.
Then use Kotlin, and take advantage of the jvm and the ecosystem, and avoid basically all the stuff you listed about the java language.
"no real reason" is a stupid take. I could list multiple, but a big one is that there are hundred java developers for each dotnet developer in my city. The java env is well tested and well understood, if anything one should argue why not use it instead of a hip and trendy alternative.
Their point about using .NET were not really valid since one of the big and best reason to use Java is that you already have a Java codebase, but things like value types and generics without type erasure aren't solved in Kotlin, so Kotlin isn't really a good answer to his not really valid point.
In what way? It's slower and has less features than the .NET runtime.
> "no real reason" is a stupid take. I could list multiple, but a big one is that there are hundred java developers for each dotnet developer in my city. The java env is well tested and well understood, if anything one should argue why not use it instead of a hip and trendy alternative.
So, your only credible excuse for using java is inertia from boomers and middle managers refusing to adapt from the standard of the early and mid 2000s?
> So, your only credible excuse for using java is inertia from boomers and middle managers refusing to adapt from the standard of the early and mid 2000s?
If you come in and freely migrate all of the Java codebases to .NET while maintaining code quality and functionalities, I'm sure many people would let you do it. If you don't understand why people stick to one language, that means that you've never worked on a big codebase, or completly ignore the business side of the developer job. In both cases, that's a lack of wisdom on your part.
I guess you missed the 'new development' part of my original comment? Obviously it would be nonsensical to port a large extant codebase to a new language and tech stack if it's just being maintained.
In the past it has sent command line arguments and the path of the current working directory, among other things, according to comments on that issue. Even if Microsoft doesn't intend to deliberately collect sensitive data, they don't seem to think it's worth putting much effort into preventing accidental data leaks from broken anonymization, unreliable opt-out mechanism, etc.
yeah, you got it. My city has very little job listings requiring .NET for actual back-ends. Whereas, there are like a thousand Java jobs and almost half mentioning Spring
These discussions inevitably end up as a flame war sooner or later.
Regardless, i actually compared Java with .NET and their web frameworks as a part of my bachelors', everything from synthetic benchmarks for encryption and data processing and transformations, to things like shuffling JSON around. Now, it's all in Latvian and was a number of years ago, so it's not entirely relevant at this point, but i did have some tangible findings.
In short:
- both Java and .NET (then Core) are inconsistent in their performance - there are certain things which are slower in one technology than other by not using external optimized libraries. For example, Java had problems with writing deeply nested dynamically generated JSON with JavaEE libraries (now Jakarta), whereas .NET Core had problems with handling large amounts of text
- their performance was largely comparable in most other tests, neither was faster by a factor of 10, like you'd see with Python and Ruby compared to either
- thus, it's largely a matter of choosing the actual frameworks that you'll want to utilize properly and consider both the job market and business factors (familiarity with the tech stack, job market etc.)
- in summary, they're close enough for it to not be a technical decision most of the time in real world circumstances (save for a few exceptions), but rather is a decision that depends on social elements
Since then:
- i don't believe that the observation of them being "close enough" has changed much, both in legacy code and otherwise
- .NET Core and now .NET 6 has improved bunches with its runtime; Core was so successful it's essentially the future of the platform (i feel bad for developers who'll be tricked into working on legacy code with the old .NET and IIS, versus the new one and Kestrel)
- JDK has improved bunches with its runtime and GC; the runtime situation is a bit complicated and cumbersome, considering the OP's article, but overall it's pretty usable, especially with frameworks like Quarkus
If you jump around the different tabs that compare which frameworks do what better, on average:
- .NET is better for plain text
- .NET is noticeably better for data updates
- Java is noticeably better for JSON serialization
- Java is noticeably better for single DB queries
- Java is noticeably better for multiple DB queries
- as for cached queries and other use cases, there's more variance
- neither is better than the other for it to matter a lot
These are probably better than me linking the bachelors' because it's done in a better controlled environment, with more resources, and a lot of people contributing to the source code of the benchmarks: https://github.com/TechEmpower/FrameworkBenchmarks/tree/mast...
In short, you're not necessarily wrong - there have indeed been great improvements to the .NET platform and it's good to see it finally being a capable and performant tech stack that you can use on *nix. But you're also not right: Java is getting similar attention, even though it's still lagging behind a few years in regards to "having its stuff together" (e.g. going from Oracle JDK to a more stable model + the JDK 8 to newer version shift, which is similarly painful with old .NET versions).
To lighten the mood, i'd consider suggesting that anyone also have a look at Go, which is similarly performant and allows you to build runtime independent executables by default, which is easier than in either .NET or Java. It's also pretty easy to write and has seen good use for the development of tools, since its startup time is a tad better than either that of Java or .NET as well. Here's the three compared: https://www.techempower.com/benchmarks/#section=data-r20&hw=...
As if implementing value types in a backwards compatible way that also modifies generics to work with them would be a trivial task..
Also, Oracle does pay plenty for the development of Java, and is a (surprisingly) good steward of the language, let’s drop all the blind hate.
And both in terms of GC and JIT, the JVM ecosystem is ahead, the reason they can be so head-to-head is that the CLR doesn’t hide lower level controls all that much, allowing for better hand-tuned programs (at the price of the resulting code not getting “automatically” faster in a possible future release)
> read: oracle doesn't want to pay their engineers to impl it and will sue you if you do it yourself) like value types, generics without type erasure, no checked exceptions, etc.
All of this is currently being implemented in project Valhalla...
I never buy into the tech stack argument that things are being worked on (e.g you mention Project Vahalla but I see this across many languages and tools). Seen this argument used on a number of different technologies. It compares a future state to a current state to put the favored tech (the future state) in an equal or better position. It usually punishes innovative platforms as well; because it dismisses any reason to take them up.
It's comparing apples to oranges - in this case .NET is also being actively worked on so may have other things by then. Compare current state only.
The truth is each platform has prioritized features relevant to its context. For what its worth in my experience while the JVM has many more JIT optimisations and the like it tends to need them more of them given the lack of some of those features you mention (e.g. value types). Whereas .NET code allows value types, better management of memory (i.e. Span), reified generics etc so the focus has been to allow the user to optimise themselves where required where still allowing for a decent performance default. Many of the optimisations in the JVM wouldn't have the same bang for buck in .NET and vice versa.
On a personal note I'm more of a fan of the .NET philosophy because the code is usually fast enough, and when I need to tune memory, avoid allocations, and do fast code it seems to offer more tools not in an unsafe context to do so. It allows a better "upper bound" of performance for core things IMO while keeping to bytecode/IL. Many benchmarks where the same level of application optimisation has occured from what I seen have confirmed this bias for me. YMMV
You’re missing the point. He claimed Oracle refuses to develop these features or will sue you if you do it yourself (they hired the guy who implemented fibers to implement them in the jvm), but they are actively working on it. The point of my comment was that OP’s claim was just patently false. I wasn’t claiming the JVM has feature parity or is better or anything of the sort.
But they ARE working on them and they ARE paying their engineeers to do it. They even hired pron to implement fibers in the jvm and didn’t sue him for doing it in quasar, which is the opposite of what you’re claiming.
> Records, switch expressions, multi line strings and that is only language changes.
None of those are features, they were desperately needed shorthands for common java idioms. This is like calling braceless if/for/while statements 'features', when they're purely syntax sugar that has fallen out of favor completely because there's been several major security vulns found in major projects due to their use and development oversight/code review failure (https://nakedsecurity.sophos.com/2014/02/24/anatomy-of-a-got...), to the point where most companies ban writing them.
Just off the top of my head:
* LINQ. Added to C# in 2007, Java didn't get streams until 2014.
* structs/value types, implemented in net framework and net core for 15+ years, but not present in java 17. Some oracle engineers have been working to implement them under project valhalla but it seems to be vaporware at this point after 8+ years of work.
* unsigned types, no plans to implement in java (though IIRC it was originally planned as part of valhalla)
* async/await
At the feature level Java is stuck in the mid 2000s. Nobody wants to do the actual work on keeping it competitive.
Thank God they didn't shove this crap in. When Loom ships (I believe the next LTS is their target, more or less), JVM will have the same concurrency story as Go does, without blue/green function split like in C#.
> unsigned types, no plans to implement in java (though IIRC it was originally planned as part of valhalla)
Not too comfortable to use functions that will compile to efficient byte code exists for them, but with the definitely coming Valhalla, it will be trivial to create a custom primitive class for unsigned ints.
> async/await
With project Loom, it will avoid the mistake of function coloring that async introduces. In a managed language, why not let the runtime automatically transform blocking calls to non-blocking, when it already knows what’s up?
> With project Loom, it will avoid the mistake of function coloring that async introduces. In a managed language, why not let the runtime automatically transform blocking calls to non-blocking, when it already knows what’s up?
Not saying it's a good or bad thing, but .NET and C# by extension has had these features for years (decades in some cases) while the only thing java has are half-baked prototypes and plans to 'maybe' implement things. In many cases these plans just get endlessly pushed back and new java major versions just become a pile of simple bugfixes which in the past were just pushed as minor jre updates.
It’s not like async/await is a must, they are on the surface just syntactic sugar.
In the background, coroutines are a strictly less useful feature than what will happen with Loom, and please show me any “promised feature” that were only half-baked prototypes? We do have one half of Valhalla (vector api) under an experimental flag with JDK 17 already, several language related JEPs were shipped already. That Loom and primitive classes take their time only mean that they are not vaporware, because these are actually ridiculously complex problems.
With your explanation everything is just a shorthand. All you really need is NAND.
Streams are a library feature, records are a language feature. Streams could be implemented outside, records could not (no lombok abominations are not records).
comparing braces to records/multi line strings/switch expressions is so funny that I won't even comment on that.
> and also what do you mean by oracle suing if you implement value types?
this one shouldn't need an explanation, oracle very commonly pursues frivolous lawsuits as a way of bullying money out of businesses that don't have the budget to fight them for years in various courts.
where does it say .net 5 was faster than openjdk? hotspot is a very sophisticated jit compiler that has probably 100 manyears put into it just in optimizations. given that .net added monomorphic/bimorphic call site devirtualization recently which is considered quite basic in the hotspot, it would be good to see real world usage comparison.
Where required there are ways to force it to inline/devirtualise yourself. For example using refied generics is one way I've seen - i.e. there is no interface/virtual casting since it takes a type that implements interface, rather than the interface itself. It allows you to make polymorphism compile time rather than runtime. Seem comparison libraries to Java (closed source) that have run much faster as a result.
I do find people comparing Java and .NET Core often are compare apples to oranges however. Working on both languages it is just my opinion but the .NET platform is newer - it has a better "base" even without the same man hours. Much of the engineering time in both ecosystems is spent optimising for code typical to that ecosystem which is affected by history/legacy like any other software system.
The safest, cheapest choice for applications that are heavily maintained is to use the most recent version. LTS is designed for legacy applications that are no longer heavily developed, and might benefit from security and bug fixes only (note that this model is new; in the past, back when there were major versions, minor updates included both patches and big features).
It also depends on your target environment, and how much control you can exert over the machine where your software will run.
Sometimes you're creating an app that other users need to run in their own environments - and in that case, targeting "latest LTS" is safer, as they may have requirements on what they can run that you don't.
True, there are, indeed, times when you can't use the current version, but note that Java applications are now encouraged to bundle their own runtime (generated with jlink).
With major releases gone, this isn't hard, and, overall cheaper and easier than upgrading less frequently. But it is some work, which is why the LTS service was added for the benefit of legacy applications. Note that under the old model, LTS didn't exist. There was a new feature release every six months that everyone had to upgrade to. The names of those releases didn't stand out as much (8u20, 8u40 for feature releases [1] as opposed to, say, 8u25, 8u45 for patches) as they do now when we did away with major releases and gave every new feature release a new integer number.
Because now the feature releases can add new APIs rather than just new JVM features as they did under the old model, this process can be slightly more work, but still significantly less work over time. As regularly maintained applications update code and dependencies regularly, anyway, this is a clear win. Not only is the upgrade process easier and cheaper, but you get to enjoy the regular and significant performance improvements that have always been part of the six-monthly feature releases, but aren't in the LTS patches.
[1]: Those feature releases under the old model also added major new features with significant changes to the VM. For example, the G1 GC and JFR were added in feature releases.
Which is quite painless, I do it since JDK 10, upgrade up to 1 week after JDK release and it was painless (with one exception around JDK 12 or 13 where spring have some issue for 1 month until I could upgrade).
Unless you want serious long term pain then you shouldn’t be more than one LTS release behind. So if you are not running on JDK 11 or later you should be strongly thinking about upgrading.