Java is too slow. Just because modern hardware allows for software to be very heavy doesn't mean that it should be acceptable for you as a developer to produce heavy software.
At the language/runtime level Java has been faster than anything else we have used on the Web with huge success (faster than PHP, Ruby/Rails, Python, Node, for example) even since 2000, and is as fast or faster than Go. It's also used in HFT - where ultimate speed means a lot.
Seriously, your argument sounds like the first year CS student argument of yore, where they hear that assembly is faster, and want to rewrite everything in assembly (fortunately today's first year CS students are more well informed).
I complain all the time about the memory consumption of Java software, they behave like they are the only ones running on a computer, but not the speed. The JVM is actually pretty fast. For sure it's a bit slower than native code but if your Java code is slow, I'm sorry but it's your code and using C++, C, Rust or whatever else faster will not make your code fast.
And just because i found it pretty interesting, here's a summary of a study that not only measures memory consumption and execution time, but also how much energy certain languages required: https://jaxenter.com/energy-efficient-programming-languages-...
My biggest issue with the JVM is the RAM consumption. Every other language, even JS beats it. GraalVM's native image feature is the only way to fix this and that is pretty sad that it took them multiple decades to fix such a glaring flaw.
Did you set a heap size for your app? Because the JVM has an eager way of consuming RAM (since then it doesn’t have to do useless work with garbage collection) - and the defaults are closer to a server config.
JVMs that most people use are optimised for repeated execution of the same code paths on long running processes. If this isn’t your use-case then lots of tuning work is required.
That fits the common Java use-case of servers and desktop applications. Not so much for Lambda instances or command-line tools, but Java isn't highly used there anyway.
The free AOT compilers have atrocious compile times (far, far worse than even Rust or Scala) and don't support all of the features so library support is extremely fragile. A lot of extremely popular Java libraries make extensive use of runtime reflection and none of the AOT compilers handle it well without a lot of extremely error prone manual configuration.
I actually like Java and the JVM but if AOT compilation and efficient memory usage is what you want Java is definitely not the language to use.
Yes, GraalVM requires a new sub ecosystem of libraries that are built with it's native image feature in mind. That means no more Spring, no more Hibernate and so on. Old codebases will not benefit and new code base require abandoning your existing Java expertise.
I agree. My main issue is with the Java zealots that come into the discussion and make it seem like anyone can just take their existing Java application and use it with an AOT compiler. The reality is that you will most likely have to make changes to your code, do a significant amount of configuration, and heavily modify or remove dependencies. Furthermore, you are isolating yourself from the huge Java community because very few people are using any of the existing AOT Java compilers.
They try to paint an extremely rosy picture of the current situation when the reality is that it's a very long way from the experience you get in Rust, Go, D, C, C++, Haskell, Ocaml or any of the languages where AOT is considered the default.
Any sufficiently large population will have someone who will literally say anything. And the common outrage trope on the internet is to rage against a straw man.
Now I haven't used GraalVM in production, but in having played around with it and doing new code from scratch, I found AOT compilation to be really good.
I think the change will come faster than you think.
You can build your leaf, domain level code into a native shared lib and still use the reflective code at the top level to compose the application.
If Java gets CTFE (compile time function evaluation), constexpr for C++ folks, much of the need for runtime reflection would disappear.
There is no reason that JITed reflective code (along with VM) can't be combined AOT code in the same program. You can already do this in Graal via front ends for llvm-ir and wasm.
As it is now, you can already mix Rust, C, C++ trivially with bytecode via LLVM ir. And for languages that compile to Wasm, GraalVM has a front end for that as well.
If Java gets CTFE (compile time function evaluation), constexpr for C++ folks, much of the need for runtime reflection would disappear.
Just to remind people that Quarkus has a "pre-compile" stage that allows code to wire itself up using reflection, annotations, config properties, etc, before the full compile. This makes start-up times much faster.
The first I used only once in 20 years of Java projects, the second is the first to go away when I get called to optimise database performance in Java applications.
This is on the comment thread of a tool to make client-side applications.
However, it's all besides the point because this tool takes Java (JVM) bytecode and translates it to WebAssembly, there's no JVM involved for end users at any point.
Slow is pretty relative. What’s your use case? Start up time is not as good as native, agreed. Arithmetic? Hotspot is pretty darn fast. Developer speed? A lot better than C/C++ at least.
> Most of the slowness I encounter though is with specific frameworks, not the language/jvm
Part of the problem is that those also happen to be the frameworks that the vast majority of the community uses.
The Java zealots also tend to ignore all of the problems associated with AOT Java compilers and the fact that it will most likely be a few years before value objects are finalized and in a released version of Java. Even then, a ton of Java developers won't be able to use any features beyond Java 8 or 11 since a lot of companies don't want to give up the ability to easily use their libraries on Android.
