Debunking the Java Performance Myth(medium.com)
medium.com
Debunking the Java Performance Myth
https://medium.com/@elliot_f/debunking-the-java-performance-myth-29b842955a24
98 comments
I'm not sure that there's a myth to be debunked, is there? Java's known to be high performance as a web application server, if good architectural choices are made. The well referred to https://www.techempower.com/benchmarks/ reliably has some of the better Java frameworks ranking near the top along with C and C++ servers.
Yeah, the title confuses me greatly. I assumed this was going to be an article about how Java is slow, debunking the myth that it’s really fast.
Really? You've never heard people joke about Java being slow? Half the programmers I've met have this cult like hate of java and cite performance as the main reason.
Java is slow, but not in this case. Tight loop java is fast. Anything that touches memory is slow. Anything that involves loading jar files is slow. Anything that involves starting the VM is slow. But tight loop java is fast, indeed, being a JIT, potentially faster than C (better branch prediction given that the JIT can optimize at runtime).
So the claim that Java is slow is true. That's why so many people hate it. The fact that Java is fast is also true.
So the claim that Java is slow is true. That's why so many people hate it. The fact that Java is fast is also true.
To be more fair, java is mostly slow on startup which which is mostly due to:
1) Swing. I have no idea what this does on startup but it is bad. This is what killed most java GUI apps. A simple AWT or SWT app will pop open while a simple swing app will take a few seconds to get started
2) Jars on systems with virus scanners. Jars are just zip files. Many virus scanners will unzip and scan a zip on every open which leads to each jar being unziped at least 2 times and often more if the app has to load more things from the jar at a later time.
3) Spring. Really spring is just a bad idea all the way through and most of the reason people hate java is Spring. Huge XML configuration files instead of code? Spring (mostly annotations now). Stupid names like AbstractSingletonProxyFactoryBean? Spring. That aside, on startup Spring will auto generate classes which really slows things down. This could have been done during the last build but spring does it at each startup which is really slow. Spring Boot has helped with startup times but it is still slower.
After startup Spring continues to kill performance. The underling code is full of maps to control request lifecycle so instead of just calling a method it has to ask "who all is configured to do something at step PreParseRequestEncoding?" then again at ParseRequestEncoding, PostParseRequestEncoding, PrePareRequestBody, ParseRequestBody.... Not real names but the idea and number of steps is. Most of the time the answer is "nobody" but it has to ask for every step that might ever need something done.
Add on top of this JPA which is super easy but quickly breaks down to a lot of DB calls. JPA is great for people who don't want to learn SQL and simple CRUD apps but anything with any amount of data will quickly slow down to thousands of DB round trips.
1) Swing. I have no idea what this does on startup but it is bad. This is what killed most java GUI apps. A simple AWT or SWT app will pop open while a simple swing app will take a few seconds to get started
2) Jars on systems with virus scanners. Jars are just zip files. Many virus scanners will unzip and scan a zip on every open which leads to each jar being unziped at least 2 times and often more if the app has to load more things from the jar at a later time.
3) Spring. Really spring is just a bad idea all the way through and most of the reason people hate java is Spring. Huge XML configuration files instead of code? Spring (mostly annotations now). Stupid names like AbstractSingletonProxyFactoryBean? Spring. That aside, on startup Spring will auto generate classes which really slows things down. This could have been done during the last build but spring does it at each startup which is really slow. Spring Boot has helped with startup times but it is still slower.
After startup Spring continues to kill performance. The underling code is full of maps to control request lifecycle so instead of just calling a method it has to ask "who all is configured to do something at step PreParseRequestEncoding?" then again at ParseRequestEncoding, PostParseRequestEncoding, PrePareRequestBody, ParseRequestBody.... Not real names but the idea and number of steps is. Most of the time the answer is "nobody" but it has to ask for every step that might ever need something done.
Add on top of this JPA which is super easy but quickly breaks down to a lot of DB calls. JPA is great for people who don't want to learn SQL and simple CRUD apps but anything with any amount of data will quickly slow down to thousands of DB round trips.
>JPA is great for people who don't want to learn SQL
That's like saying Java is for people who don't want to learn C...or C is for people who don't want to learn assembly.
It's the right tool for the right job. If you use it for everything, it's no so good.
That's like saying Java is for people who don't want to learn C...or C is for people who don't want to learn assembly.
It's the right tool for the right job. If you use it for everything, it's no so good.
I like Spring, I find it makes Java development pleasant, plus I have unfair access to the Spring team members by working for the same company. So I'll bite.
> Huge XML configuration files instead of code? Spring (mostly annotations now).
Spring 3, yes. Spring 4 and 5, no. XML has not been the blessed configuration approach for ~4 years.
> Stupid names like AbstractSingletonProxyFactoryBean? Spring.
Java is a language that has evolved enormously in expressiveness since Spring began, meaning heavyweight Go4 patterns were necessary early on to maintain a flexible substrate with a uniform interface serving very many use cases? Spring.
> That aside, on startup Spring will auto generate classes which really slows things down.
I believed this urban legend too.
Dave Syer, who is understandably interested in Spring criticism, has done more empirical investigation than anyone on this topic[0].
The tl;dr is that boot time is proportional to total classes loaded. That's all, that's it.
In-memory reflection operations are hilariously, stupidly, insanely faster than I/O. The JVM fetches and loads classes individually. So if you have a lot of classes, it takes a longer time to load.
The other thing to bear in mind is that Spring relies on this much less than it used to. As the language and JVM have evolved, so has Spring.
> The underling code is full of maps to control request lifecycle ... Not real names but the idea and number of steps is.
Are you talking about servlet filters? Because any web framework is going to have a few of these. Spring MVC adds a handful and all of them can be removed, replaced or added to. Spring Security adds a bunch and all of them can be removed, replaced or added to. But the defaults are chosen because of feedback, not just for the heck of it.
> Add on top of this JPA which is super easy but quickly breaks down to a lot of DB calls. JPA is great for people who don't want to learn SQL and simple CRUD apps but anything with any amount of data will quickly slow down to thousands of DB round trips.
In general, yes, I agree that JPA is a PITA. For a small to medium system I would try to avoid it where possible. For a sufficiently large codebase -- thousands of domain objects, dozens or hundreds of programmers -- it might be a necessary evil.
Mind you, if you want to see a world where the database goes from abused to outright mocked and ignored, pay a visit to Rails land. It drives me batty.
[0] https://github.com/dsyer/spring-boot-startup-bench, particularly https://github.com/dsyer/spring-boot-startup-bench/tree/mast...
> Huge XML configuration files instead of code? Spring (mostly annotations now).
Spring 3, yes. Spring 4 and 5, no. XML has not been the blessed configuration approach for ~4 years.
> Stupid names like AbstractSingletonProxyFactoryBean? Spring.
Java is a language that has evolved enormously in expressiveness since Spring began, meaning heavyweight Go4 patterns were necessary early on to maintain a flexible substrate with a uniform interface serving very many use cases? Spring.
> That aside, on startup Spring will auto generate classes which really slows things down.
I believed this urban legend too.
Dave Syer, who is understandably interested in Spring criticism, has done more empirical investigation than anyone on this topic[0].
The tl;dr is that boot time is proportional to total classes loaded. That's all, that's it.
In-memory reflection operations are hilariously, stupidly, insanely faster than I/O. The JVM fetches and loads classes individually. So if you have a lot of classes, it takes a longer time to load.
The other thing to bear in mind is that Spring relies on this much less than it used to. As the language and JVM have evolved, so has Spring.
> The underling code is full of maps to control request lifecycle ... Not real names but the idea and number of steps is.
Are you talking about servlet filters? Because any web framework is going to have a few of these. Spring MVC adds a handful and all of them can be removed, replaced or added to. Spring Security adds a bunch and all of them can be removed, replaced or added to. But the defaults are chosen because of feedback, not just for the heck of it.
> Add on top of this JPA which is super easy but quickly breaks down to a lot of DB calls. JPA is great for people who don't want to learn SQL and simple CRUD apps but anything with any amount of data will quickly slow down to thousands of DB round trips.
In general, yes, I agree that JPA is a PITA. For a small to medium system I would try to avoid it where possible. For a sufficiently large codebase -- thousands of domain objects, dozens or hundreds of programmers -- it might be a necessary evil.
Mind you, if you want to see a world where the database goes from abused to outright mocked and ignored, pay a visit to Rails land. It drives me batty.
[0] https://github.com/dsyer/spring-boot-startup-bench, particularly https://github.com/dsyer/spring-boot-startup-bench/tree/mast...
I will admit that spring has gotten a lot better recently, but it is still a mess (IMHO of course) and this "benchmark" seems to agree.
The biggest issue I have with spring isn't performance but is the huge internal state that is the basis of Spring's DI.
After a few versions you end up with code that depends on bean named 'Abd" to preform a task, but in the next version is renamed to "Abc" which fixes the typo, but makes all the documentation off. And the 3 other classes that also needed that task still look for it under the name "Abd". And then the next major version replaces this entire module and the bean name is now "Xyz". To me this IS spring programming. Googling the DI names and trying them one by until you get the desired run time functionality.
I've had apps in production with unused beans defined (It only had 1 function that only throw an exception and was never called) but had to be defined or something would break. Multiple team members wasted some free time trying to locate the code that was requiring that bean but nobody could ever figure it out. At some point everybody gave up, it was easier to just let it be.
Most developers have little to no idea what is actually going on inside their spring apps (or even what half their dependencies are). When a struts like vulnerability comes along in the spring world it is going to be a massive PITA to fix. With how complex this all is I have little doubt that a vulnerability exist somewhere in there.
The biggest issue I have with spring isn't performance but is the huge internal state that is the basis of Spring's DI.
After a few versions you end up with code that depends on bean named 'Abd" to preform a task, but in the next version is renamed to "Abc" which fixes the typo, but makes all the documentation off. And the 3 other classes that also needed that task still look for it under the name "Abd". And then the next major version replaces this entire module and the bean name is now "Xyz". To me this IS spring programming. Googling the DI names and trying them one by until you get the desired run time functionality.
I've had apps in production with unused beans defined (It only had 1 function that only throw an exception and was never called) but had to be defined or something would break. Multiple team members wasted some free time trying to locate the code that was requiring that bean but nobody could ever figure it out. At some point everybody gave up, it was easier to just let it be.
Most developers have little to no idea what is actually going on inside their spring apps (or even what half their dependencies are). When a struts like vulnerability comes along in the spring world it is going to be a massive PITA to fix. With how complex this all is I have little doubt that a vulnerability exist somewhere in there.
The Struts vulnerability was less about Struts and more about the universal difficulty of dependency management.
Which Spring Boot ameliorates by providing starter POMs. Curated, levelled, updated collections of dependencies for common cases. No need to play whack-a-dep with Maven or Gradle. No need to track 50 different dependencies yourself.
The thing is: I don't care how Spring does the magic. I care that I don't have to care.
I came to Spring and Java-for-real development relatively late -- by fluke I was on what is almost certainly the first Boot production app ever deployed, back in early 2014.
Later I got a chance to see the primordial world of Spring 3. I understand the residual hate.
Which Spring Boot ameliorates by providing starter POMs. Curated, levelled, updated collections of dependencies for common cases. No need to play whack-a-dep with Maven or Gradle. No need to track 50 different dependencies yourself.
The thing is: I don't care how Spring does the magic. I care that I don't have to care.
I came to Spring and Java-for-real development relatively late -- by fluke I was on what is almost certainly the first Boot production app ever deployed, back in early 2014.
Later I got a chance to see the primordial world of Spring 3. I understand the residual hate.
> Are you talking about servlet filters? Because any web framework is going to have a few of these. Spring MVC adds a handful and all of them can be removed, replaced or added to. Spring Security adds a bunch and all of them can be removed, replaced or added to. But the defaults are chosen because of feedback, not just for the heck of it.
Even ignoring filters, it seems to me that Spring brings a lot of overhead. Adding an annotation to a method sometimes means that would appear to be a direct call between two of your beans is in fact separated by 10 method calls on a stack trace. In many cases this is not an issue (expecially in "enterprise" applications), but it is clear to me that performance is not really one of the main concerns of spring developers.
Even ignoring filters, it seems to me that Spring brings a lot of overhead. Adding an annotation to a method sometimes means that would appear to be a direct call between two of your beans is in fact separated by 10 method calls on a stack trace. In many cases this is not an issue (expecially in "enterprise" applications), but it is clear to me that performance is not really one of the main concerns of spring developers.
> In-memory reflection operations are hilariously, stupidly, insanely faster than I/O. The JVM fetches and loads classes individually. So if you have a lot of classes, it takes a longer time to load.
One thing that I have noticed is that with all these annotation, the Java compiler is not doing much any more. Java has effectively became a dynamic language (as in an interpreted language) where errors are only visible at runtime when hitting some specific method.
Coupled with the really slow startup time (again, I talk about Spring Boot--I get a steady 10s vs 0.01s for Go, same functionality), it makes developing a simple CRUD a pain compared to both Go or Python/Ruby...
One thing that I have noticed is that with all these annotation, the Java compiler is not doing much any more. Java has effectively became a dynamic language (as in an interpreted language) where errors are only visible at runtime when hitting some specific method.
Coupled with the really slow startup time (again, I talk about Spring Boot--I get a steady 10s vs 0.01s for Go, same functionality), it makes developing a simple CRUD a pain compared to both Go or Python/Ruby...
I've never seen IntelliJ or Eclipse fail to work out how to get to the definition I'm looking for.
For Ruby I see RubyMine doing what amounts to a fulltext search. It's next to useless.
For startup time, see my notes on the JVM and the link to Dave Syer's notes.
There's also the devtools starter to ease the JVM reload pain. Which to me is by far the biggest suckiness of the thing.
For Ruby I see RubyMine doing what amounts to a fulltext search. It's next to useless.
For startup time, see my notes on the JVM and the link to Dave Syer's notes.
There's also the devtools starter to ease the JVM reload pain. Which to me is by far the biggest suckiness of the thing.
> JPA
I'd like to see some reallife-ish comparisons with Jooq
I'd like to see some reallife-ish comparisons with Jooq
I don't even know what to say about items #1 and #2 here. Unless you work for JetBrains, is Swing relevant to anything? And virus scanners shouldn't be an issue unless you're running on a Windows server, in which case I question whether you know what you're doing.
If you really believe that JPA means "you don't have to understand SQL", then you definitely don't know what you're doing.
As for Spring, I get so tired of reading lengthy critiques that boil down to:
1. "It uses XML! (or at least it did 10 years ago, when my personal experience with it was last up-to-date)"
2. "It has some classes with long names! Named after design patterns that I don't like!"
By all means, don't use Spring if you don't want to. But know that Spring is very modular, letting you include or exclude whatever you like, and the core is rather light. If you're not using at least some of it, then you're probably re-writing it... and doing a worse job than they did. Either way, stop ranting about it on web forums if your knowledge is from 2007.
If you really believe that JPA means "you don't have to understand SQL", then you definitely don't know what you're doing.
As for Spring, I get so tired of reading lengthy critiques that boil down to:
1. "It uses XML! (or at least it did 10 years ago, when my personal experience with it was last up-to-date)"
2. "It has some classes with long names! Named after design patterns that I don't like!"
By all means, don't use Spring if you don't want to. But know that Spring is very modular, letting you include or exclude whatever you like, and the core is rather light. If you're not using at least some of it, then you're probably re-writing it... and doing a worse job than they did. Either way, stop ranting about it on web forums if your knowledge is from 2007.
> And virus scanners shouldn't be an issue unless you're running on a Windows server, in which case I question whether you know what you're doing.
Is "the server" the only place where code is run today? That is a sad image for privacy and user sovereignty. I certainly still run a lot of code on my local system, and I wish more people did the same.
Is "the server" the only place where code is run today? That is a sad image for privacy and user sovereignty. I certainly still run a lot of code on my local system, and I wish more people did the same.
I (sadly) have production experience from within the last year. I don't use Spring by choice, but it still gets forced on me by coworkers and teammates, so I reserve the right to complain.
I've heard the "you're probably re-writing it... and doing a worse job than they did" argument so many times, is this on the spring forums or something?
I've heard the "you're probably re-writing it... and doing a worse job than they did" argument so many times, is this on the spring forums or something?
Not sure about using Spring for creating Web services (most use JAX-RS), but otherwise Spring is great. Not sure what we would do without it. The two major aspects are the dependency injection and just sheer number of service libraries to do anything imaginable.
I generally try to stay away from strong opinions and assume that when something has an opinion there may be a reason behind it, but in the case of Spring and Java, I have concluded that those not using or familiar with Spring are simply clueless jokers.
I generally try to stay away from strong opinions and assume that when something has an opinion there may be a reason behind it, but in the case of Spring and Java, I have concluded that those not using or familiar with Spring are simply clueless jokers.
Java is slow compared to C/C++ and Fortran and comparable with SBCL / Rust. But it is fast compared to Python, JavaScript, PHP and Ruby.
It's the rise of these languages that confuses me.
They somehow got away with the 'fast enough' argument whilst Java is constantly being compared to languages that are designed for fine tuning for the target architecture.
In my mind it is Java that is 'fast enough' and,with Java 8, very expressive. The continued success of these incredibly slow interpreted languages in enterprises where you need to buy servers feels like an anti-pattern.
It's the rise of these languages that confuses me.
They somehow got away with the 'fast enough' argument whilst Java is constantly being compared to languages that are designed for fine tuning for the target architecture.
In my mind it is Java that is 'fast enough' and,with Java 8, very expressive. The continued success of these incredibly slow interpreted languages in enterprises where you need to buy servers feels like an anti-pattern.
From my perspective, choosing Python over Java (on Linux) around 2001:
It was easy to find benchmarks showing that Java was fast. But Java turned out to be slower in every situation we might consider using it.
Command-line applications were slower because the JVM took ages to start.
GUI applications were slower, apparently because Python would use C-implemented widgets while Java would do much of the drawing itself.
Web applications were slower without any good excuse as far as I could see, but something in the application server that was the mainstream way of doing things added more per-request overhead than starting a whole new Python interpreter via CGI.
CPU-intensive operations (I remember image resizing in particular) were slower because, again, you ended up comparing the JVM against a well-written C extension.
It was easy to find benchmarks showing that Java was fast. But Java turned out to be slower in every situation we might consider using it.
Command-line applications were slower because the JVM took ages to start.
GUI applications were slower, apparently because Python would use C-implemented widgets while Java would do much of the drawing itself.
Web applications were slower without any good excuse as far as I could see, but something in the application server that was the mainstream way of doing things added more per-request overhead than starting a whole new Python interpreter via CGI.
CPU-intensive operations (I remember image resizing in particular) were slower because, again, you ended up comparing the JVM against a well-written C extension.
I would say that of these, most are still true-ish, except web apps and some CPU-intensive cases. Where you have a long-running service, Java shines.
Java marketing was a disaster. Remember when it was going to be the replacement for browsers? It was not a great way to engender goodwill.
Java marketing was a disaster. Remember when it was going to be the replacement for browsers? It was not a great way to engender goodwill.
I think that the part this is missing is that when comparing Java to Python/Ruby part of the argument for the latter is the dynamic language aspect. To the folks making these statements, Java is seen as involving all the headaches of those faster languages but none of the advantages whereas Python/Ruby have slower runtimes but come with potentially faster development time, etc. I personally don't like this comparison but it's how I see it made typically.
Random anecdote which led me to stop calling Java slow: I'll never forget the time I took a 3000ish line Python program which had been heavily performance tuned and thus completely impenetrable. I converted it to a dumbest-scheme-possible naive implementation in Java weighing in at roughly 100 lines , expecting that to be a first pass. It turned out that the Java implementation was many times faster so we called it good enough and moved on with life. Obviously YMMV and all of that
Random anecdote which led me to stop calling Java slow: I'll never forget the time I took a 3000ish line Python program which had been heavily performance tuned and thus completely impenetrable. I converted it to a dumbest-scheme-possible naive implementation in Java weighing in at roughly 100 lines , expecting that to be a first pass. It turned out that the Java implementation was many times faster so we called it good enough and moved on with life. Obviously YMMV and all of that
Do multi-threaded workloads, which a lot of high performance workloads are, Java has also the potential to be faster than C++ due to garbage collection and threading aware optimizations it can make. Memory allocation, especially when memory lifecycle spans threads can be expensive in C++.
"A JVM does that???" by Cliff Click is a good introduction on what can go in the background.
"A JVM does that???" by Cliff Click is a good introduction on what can go in the background.
so write a specialized GC for the task in C or C++.
C++ can always win!
JVM has hotspot? use profile guided optmization in C!
There is no escape!
C++ can always win!
JVM has hotspot? use profile guided optmization in C!
There is no escape!
If you are one of the three people in the world that can do it. ;-)
Just use an arena allocator (or similar) where appropriate. It's not difficult and it's how C, C++ and Rust win all micro benchmarks that involve memory allocation: http://benchmarksgame.alioth.debian.org/u64q/binarytrees.htm...
I just looked at the list for where my beloved cherrypy might sit. It is almost at the bottom. But that does not matter because writing webapps with it is easy and fun.
As I see it, most sites don't need the hardware they're allocated. If you want to sleep on the weekend, you need at least two and probably three servers. That is almost certainly in the realms of 10x what most applications actually need. So a language that is 10x slower than C isn't a big deal.
CherryPy fits nicely into this window of opportunity, but as soon as you have to go back to your boss and say "I think we need a bigger boat" someone should be asking questions about library and language choices, at the very least there should be a conversation about prototypes vs production architectures.
Similarly, Python and the dynamic languages are 'fast enough' because in the 90s the bottleneck was IO, not CPU. That is still true, but is becoming less true. SSDs rapidly closed that gap, and it looks like memristor storage could mean that non-volatile RAM is as large as SSD and as fast as DRAM is today.
The dynamic language decision to focus on single threaded performance is also smart, but that will stop being true when CPU have hundreds of cores, instead of 10s. Synchronized access to cache is 100x slower than regular access. So to see benefit for work loads other than the "embarrassingly parallel" with multi-core you need around 100 threads. The new competition in the CPU market might see the first 100 core die on the market in 5 years.
The trend towards 'serverless' could be even worse for dynamic/interpreted languages. Smaller slices of billing will show that the same service written in Java vs Python cost 5-10x less. That was harder to show when you had to pay for at least two servers for every deployed service, now it will be very clear to CFOs how much language choice affects their bottom line.
What this means is that the perceived difference in performance between Java and Python can only grow over the next 5-10 years. If Java continues to gross you out, I'd be looking to pad your resume with something like Clojure / Go / Rust. High productivity, high performance languages are here and their relevance is growing.
CherryPy fits nicely into this window of opportunity, but as soon as you have to go back to your boss and say "I think we need a bigger boat" someone should be asking questions about library and language choices, at the very least there should be a conversation about prototypes vs production architectures.
Similarly, Python and the dynamic languages are 'fast enough' because in the 90s the bottleneck was IO, not CPU. That is still true, but is becoming less true. SSDs rapidly closed that gap, and it looks like memristor storage could mean that non-volatile RAM is as large as SSD and as fast as DRAM is today.
The dynamic language decision to focus on single threaded performance is also smart, but that will stop being true when CPU have hundreds of cores, instead of 10s. Synchronized access to cache is 100x slower than regular access. So to see benefit for work loads other than the "embarrassingly parallel" with multi-core you need around 100 threads. The new competition in the CPU market might see the first 100 core die on the market in 5 years.
The trend towards 'serverless' could be even worse for dynamic/interpreted languages. Smaller slices of billing will show that the same service written in Java vs Python cost 5-10x less. That was harder to show when you had to pay for at least two servers for every deployed service, now it will be very clear to CFOs how much language choice affects their bottom line.
What this means is that the perceived difference in performance between Java and Python can only grow over the next 5-10 years. If Java continues to gross you out, I'd be looking to pad your resume with something like Clojure / Go / Rust. High productivity, high performance languages are here and their relevance is growing.
I think it’s possibly an age thing. Java really _was_ pretty slow in the mid 90s, and the reputation has never quite gone away for people exposed to it then. People only exposed in, say, the mid-noughties have less reason to ever get that impression, though.
Actually, Java was very slow 15 years ago and that might be the reason for that cult.
Decades ago, when Java was new, the VMs were not very good, and the comparison was with C and C++, it was commonly said that Java was slow.
But these days, Java VMs are vastly better and Java is competing with languages like Python and Ruby. The way things are today, the assumption is that Java is faster than its competition.
But these days, Java VMs are vastly better and Java is competing with languages like Python and Ruby. The way things are today, the assumption is that Java is faster than its competition.
Java desktop applications tend to be slow and bloated. Java server applications tend to be pretty ok if well designed.
For desktop applications you suffer some more from innate disadvantages of JITs and the common graphics libs. People experience Java when using eclipse and minecraft and so perceive it as slow. When a java server provided data fast to a wevsite, people don't know that is java.
For desktop applications you suffer some more from innate disadvantages of JITs and the common graphics libs. People experience Java when using eclipse and minecraft and so perceive it as slow. When a java server provided data fast to a wevsite, people don't know that is java.
yup me too
"If good architectural choices are made" is a high bar, considering that many popular Java frameworks (not the ones high up on the list) have already made bad choices (performance-wise) for you.
Well, true - but the highest ranked Python(#1) framework is at 25%, with probably a dozen or so Java configurations above it in the list. If low latency and high throughput is a primary goal (i.e. you really need scale) then you're probably going to know about gemini, undertow, grizzly, etc if you're in the Java ecosystem.
(#1 mentioned since it's one of the two languages compared to Java in TFA).
(#1 mentioned since it's one of the two languages compared to Java in TFA).
I think Java being slow was the reality 20 years ago, a widely believed myth 10 years ago, and something that no one but dinosaurs believes now.
Well, I have not taken a look at the implementation yet, but java is certainly known for delivering a decent performance even if the programmer is a little careless regarding perfromance.
In Go on the other hand, doing simple 'mistakes' like declaring a variable inside a loop can bring you to performance hell:
Declaration in a loop:
Src: https://nopaste.xyz/?68c6800acd9200d6#mDstI36uBPBU4Td8k//GNC...
In Go on the other hand, doing simple 'mistakes' like declaring a variable inside a loop can bring you to performance hell:
Declaration in a loop:
var sum int
for i := 0; i < n; i++ {
x := i + i
sum = x - i
}
var sum int
var x int
for i := 0; i < n; i++ {
x = i + i
sum = x - i
}
BenchmarkInLoop-8 2000000000 0.40 ns/op
BenchmarkOutLoop-8 2000000000 0.47 ns/op
Src: https://nopaste.xyz/?68c6800acd9200d6#mDstI36uBPBU4Td8k//GNC...
Declaring a primitive variable inside vs outside a loop in c or c++ will have no effect when compiled with optimizations on by any major compiler. For non-primitive types it will depend on a number of factors, and the better choice for perf could go either way.
Yes, because if the loop is not always-executing, it may be cheaper to not initialize the complex object, even if it is safe to so.
I've also (recently) had poor performance on MSVC when "outside the loop" meant "a function argument", for a type that was essentially a struct wrapping a single primitive. It ended up being ABI weirdness that was confusing MSVC (and forceinline ended up fixing it).
This is a common compiler optimization. It says little about a language, just the compiler in use.
Any decent C/C++ compiler will give the same code. For example, this:
int f1(int n) {
int sum = 0;
for (int i = 0; i < n; i++) {
int x = i + i;
sum = x - i;
}
return sum;
}
int f2(int n) {
int sum = 0;
int x;
for (int i = 0; i < n; i++) {
x = i + i;
sum = x - i;
}
return sum;
}
.file "loop.c"
.text
.globl f1
.type f1, @function
f1:
.LFB0:
.cfi_startproc
testl %edi, %edi
jle .L4
movl $0, %eax
.L3:
addl $1, %eax
cmpl %eax, %edi
jne .L3
subl $1, %eax
ret
.L4:
movl $0, %eax
ret
.cfi_endproc
.LFE0:
.size f1, .-f1
.globl f2
.type f2, @function
f2:
.LFB1:
.cfi_startproc
testl %edi, %edi
jle .L9
movl $0, %eax
.L8:
addl $1, %eax
cmpl %eax, %edi
jne .L8
subl $1, %eax
ret
.L9:
movl $0, %eax
ret
.cfi_endproc
.LFE1:
.size f2, .-f2
.ident "GCC: (GNU) 7.2.0"
.section .note.GNU-stack,"",@progbits
What go compiler are you using? On my machine those run in exactly the same amount of time (go version go1.9 linux/amd64
).
$ ./tmp.test -test.bench .
goos: linux
goarch: amd64
BenchmarkInLoop-4 2000000000 0.46 ns/op
BenchmarkOutLoop-4 2000000000 0.46 ns/op
PASS
(pprof) disasm fast
Total: 1.95s
ROUTINE ======================== _/tmp.fast
970ms 970ms (flat, cum) 49.74% of Total
. . 4ed7c0: MOVQ 0x8(SP), AX ;main_test.go:23
. . 4ed7c5: XORL CX, CX
. . 4ed7c7: MOVQ CX, DX
. . 4ed7ca: JMP 0x4ed7d6 ;main_test.go:26
660ms 660ms 4ed7cc: LEAQ 0x1(CX), BX ;_/tmp.fast main_test.go:26
110ms 110ms 4ed7d0: MOVQ CX, DX
170ms 170ms 4ed7d3: MOVQ BX, CX
30ms 30ms 4ed7d6: CMPQ AX, CX
. . 4ed7d9: JL 0x4ed7cc ;main_test.go:26
. . 4ed7db: MOVQ DX, 0x10(SP) ;main_test.go:30
(pprof) disasm slow
Total: 1.95s
ROUTINE ======================== _/tmp.slow
960ms 960ms (flat, cum) 49.23% of Total
. . 4ed790: MOVQ 0x8(SP), AX ;main_test.go:14
. . 4ed795: XORL CX, CX
. . 4ed797: MOVQ CX, DX
. . 4ed79a: JMP 0x4ed7a6 ;main_test.go:16
690ms 690ms 4ed79c: LEAQ 0x1(CX), BX ;_/tmp.slow main_test.go:16
100ms 100ms 4ed7a0: MOVQ CX, DX
100ms 100ms 4ed7a3: MOVQ BX, CX
70ms 70ms 4ed7a6: CMPQ AX, CX
. . 4ed7a9: JL 0x4ed79c ;main_test.go:16
. . 4ed7ab: MOVQ DX, 0x10(SP) ;main_test.go:20Well, the assembler looks the same to me too, but I can confirm different runtimes on two different machines (fast is always faster here).
$ ./main.test -test.bench . -test.cpuprofile=test.profile
goos: linux
goarch: amd64
BenchmarkInLoop-8 2000000000 0.42 ns/op
BenchmarkOutLoop-8 2000000000 0.47 ns/op
PASS
(pprof) disasm fast
Total: 1.86s
ROUTINE ======================== command-line-arguments.fast
990ms 990ms (flat, cum) 53.23% of Total
. . 4ed7b0: MOVQ 0x8(SP), AX ;mem_test.go:16
. . 4ed7b5: XORL CX, CX
. . 4ed7b7: MOVQ CX, DX
. . 4ed7ba: JMP 0x4ed7c6 ;mem_test.go:19
650ms 650ms 4ed7bc: LEAQ 0x1(CX), BX ;command-line-arguments.fast mem_test.go:19
. . 4ed7c0: MOVQ CX, DX ;mem_test.go:19
10ms 10ms 4ed7c3: MOVQ BX, CX ;command-line-arguments.fast mem_test.go:19
330ms 330ms 4ed7c6: CMPQ AX, CX
. . 4ed7c9: JL 0x4ed7bc ;mem_test.go:19
. . 4ed7cb: MOVQ DX, 0x10(SP) ;mem_test.go:23
(pprof) disasm slow
Total: 1.86s
ROUTINE ======================== command-line-arguments.slow
870ms 870ms (flat, cum) 46.77% of Total
. . 4ed780: MOVQ 0x8(SP), AX ;mem_test.go:7
. . 4ed785: XORL CX, CX
. . 4ed787: MOVQ CX, DX
. . 4ed78a: JMP 0x4ed796 ;mem_test.go:9
560ms 560ms 4ed78c: LEAQ 0x1(CX), BX ;command-line-arguments.slow mem_test.go:9
. . 4ed790: MOVQ CX, DX ;mem_test.go:9
20ms 20ms 4ed793: MOVQ BX, CX ;command-line-arguments.slow mem_test.go:9
290ms 290ms 4ed796: CMPQ AX, CX
. . 4ed799: JL 0x4ed78c ;mem_test.go:9
. . 4ed79b: MOVQ DX, 0x10(SP) ;mem_test.go:13 $ go version
go version go1.9.1 linux/amd64Damn, I will have to take a look at aiohttp. That's impressive, I'm glad that python, my favorite language, can have that kind of performance.
I think an important element in comparing Go to Java for webserver apps is language design. While Java 8 and Go's performance may be similar in small single-threaded request handler benchmarks, Java's baseline design encourages the creation of lots of expensive runtime abstractions, and makes parallelism difficult. Go on the other hand encourages a minimum of abstractions and makes parallelism trivial. That means that the marginal cost of business logic is much higher in Java, in both response times (due to unnecessary serialization) and overall computation. Some of this can be averted by careful engineering, but Java definitely isn't a "pit of success" in this regard - the easiest thing to do is usually the wrong thing.
> Java's baseline design encourages the creation of lots of expensive runtime abstractions
Abstractions yes, expensive, perhaps not. One of the nice things about Java is that the JIT can collapse a lot of abstraction at runtime. Not all of it, but a lot of it. I am skeptical about the idea that Java naturally guides programmers towards expensive abstractions.
> and makes parallelism difficult
Presumably, you mean something like "makes lightweight concurrency difficult, because all the backend APIs for database access etc are blocking", which is unfortunately true.
Abstractions yes, expensive, perhaps not. One of the nice things about Java is that the JIT can collapse a lot of abstraction at runtime. Not all of it, but a lot of it. I am skeptical about the idea that Java naturally guides programmers towards expensive abstractions.
> and makes parallelism difficult
Presumably, you mean something like "makes lightweight concurrency difficult, because all the backend APIs for database access etc are blocking", which is unfortunately true.
I think perhaps it's more of a "pure OO" approach than the language itself. I've seen plenty of Java and C++ code where there is one interface class for every concrete class, even when just one concrete class is ever implemented, for example. I've also seen cases where some "factory" pattern is force-fit into the architecture, and the objects it creates are kinda sorta related, but ought not be in code. It gets exponentially worse as more interfaces and more levels in a hierarchy are allowed.
The compiler isn't always going to be able to collapse or elide these.
The compiler isn't always going to be able to collapse or elide these.
The thing about Go I do not get is why somebody would go back to essentially C to develop modern code? The tools are lacking, the language features are lacking, the libraries are lacking, so why?
Go is still garbage collected language, so in a sense it combines the most problematic features of C and Java.
Go is still garbage collected language, so in a sense it combines the most problematic features of C and Java.
One more dumb test not even giving the code and test environment fully. Btw, this tests are useless. Add some real usecase, a database, some number crunching, jobs execution and see python fail even more for example.
The JVM has indeed matured to the point where it's on par with other VM style languages, and better than interpreted languages. This wasn't always the case: early in Java's lifetime it was a slow, memory intensive hog. That stigma has stuck.
That said, it's still pretty heavyweight (both the language and the runtime).
It also wouldn't be my first choice for compute intensive tasks (for example, a non-toy ray tracer). It would do the job eventually, but at a cost. Of course, I wouldn't pick Go or Python either.
That said, it's still pretty heavyweight (both the language and the runtime).
It also wouldn't be my first choice for compute intensive tasks (for example, a non-toy ray tracer). It would do the job eventually, but at a cost. Of course, I wouldn't pick Go or Python either.
Reminds me people blaming clojure slow boot on the JVM when it was in fact clojure tooling that took time.
Things aren't straightforward, we need to go deep before concluding. Profilers, profilers, profilers.
Things aren't straightforward, we need to go deep before concluding. Profilers, profilers, profilers.
There are people in college or entering the workforce who weren't even alive during the "Java is slow" period. The HotSpot JIT has been around since 1999. I wonder if we'll ever be able to let this go.
Would be interested in seeing Elixir/Phoenix compared here. I've seen some amazing scalability figures from those folks: http://phoenixframework.org/blog/the-road-to-2-million-webso...
For posterity sake, throw in Ruby on Rails as well.
For posterity sake, throw in Ruby on Rails as well.
Elixir is more focused on concurrent performance than raw performance. It’s still very fast but favors consistency above all else. I remember seeing a great benchmark that compared Elixir to Python and Go where they charted the variability of response times. Python and Go were very spikey with Go producing the fastest overall time. Elixir was extremely steady. Makes it an ideal choice for real time ops, holding millions of web sockets, ensuring a heavy process doesn’t affect the experience of everything else that’s executing.
You’ll also get natural clustering ability and a level of fault tolerance that’s almost silly.
I’ve been trying to find the time to demonstrate this with the tech empower benchmarks honestly. I want to see what will happen if you run all of them at the same time for a particular platform.
You’ll also get natural clustering ability and a level of fault tolerance that’s almost silly.
I’ve been trying to find the time to demonstrate this with the tech empower benchmarks honestly. I want to see what will happen if you run all of them at the same time for a particular platform.
It baffles me how people give Elixir the credit for this. Everything you mentioned here have nothing to do with Elixir, but with how Erlang and its preemptive scheduler were optimized for soft real-time apps.
BEAM gets the credit but the parent mentioned Elixir so that’s how I responded. It’s just quicker than writing Elixir/Erlang/BEAM/OTP everytime.
Wasn’t trying to misappropriate the credit.
Wasn’t trying to misappropriate the credit.
Agree that Erlang is what gives most of the performance and scalability benefits to Elixir and as such I should mention Erlang / BEAM to give due credit. However Elixir is my recommended target language for any developers who want an easy to learn language with a great community. The phoenix framework and powerful meta programming constructs are unique to Elixir.
Yep, Elixir mostly just changed the syntax to something more C like instead of ant turds. Erlang is a beautiful design but the prolog syntax never really caught on.
Flask is synchronous and it shouldn't be labeleld "Python 2.7 or Python 3.6".
Comparing that to async frameworks is not quite fair.
(Also is SpringBoot async?)
Spring Boot can be both reactive or ordinary thread pool based to serve requests or anything from the stack really. It is very very powerful framework and comparing something barebones to Boot is really dumb. Not to mention that author intentionally made java look like a monster when he could use some simple tweaks to reduce jvm memory usage by much and he hid what dependencies really imported. And also if he did not like Boot he could just fire barebons Jetty up and use 20mb heap tops.
Spring Boot really comes away awful in this article (and the one he links in the article). I have mostly worked on projects using Dropwizard and Spring Boot and have come to like some of the easy to use abstractions but I have only scratched the surface of these frameworks, I assume, and most of it I will probably never use. Most of the time it did not matter that much to give the Server a GB more memory but recently we had some real issues with CloudFoundry. To me it seems that it's not possible to somehow magically tweak Spring Boot to behave better. So I came to wonder, what other framework would strike a better balance? Maybe not offer the crazy specialised stuff Spring offers or maybe needing some more work to get something to run but then offer vastly better memory and speed charactersitics?
I guess one way would be to implement the things I actually use myself with less abstractions but that honsetly feels very daunting to me. The Java ecosystem is so vast and between Handling the Requests, DB access (with or without ORM), persistance, caching, security, I really have no clue on where to even start doing something like this myself. If someone more seasoned here has some input, I would be highly interested!
I guess one way would be to implement the things I actually use myself with less abstractions but that honsetly feels very daunting to me. The Java ecosystem is so vast and between Handling the Requests, DB access (with or without ORM), persistance, caching, security, I really have no clue on where to even start doing something like this myself. If someone more seasoned here has some input, I would be highly interested!
> Most of the time it did not matter that much to give the Server a GB more memory but recently we had some real issues with CloudFoundry.
A long-standing difficulty with the Java Buildpack was working out how much memory to give it -- the Garden container engine is particularly ruthless to any process going above the allocated memory limit. I believe it got a lot of attention in v4 (edit: see [0] and [1]).
My personal pet peeve is that the memory quota is identical for staging and runtime. Which means that memory-intensive staging operations force you to have wasteful runtime memory allocations. I mostly noticed this when using Rails apps that pull in Nokogiri -- it gets compiled during staging and often that causes a lot of memory usage.
Disclosure: I work for Pivotal, we do the majority of Cloud Foundry engineering. We also sponsor Spring.
[0] https://www.cloudfoundry.org/just-released-java-buildpack-4-...
[1] https://github.com/cloudfoundry/java-buildpack-memory-calcul...
A long-standing difficulty with the Java Buildpack was working out how much memory to give it -- the Garden container engine is particularly ruthless to any process going above the allocated memory limit. I believe it got a lot of attention in v4 (edit: see [0] and [1]).
My personal pet peeve is that the memory quota is identical for staging and runtime. Which means that memory-intensive staging operations force you to have wasteful runtime memory allocations. I mostly noticed this when using Rails apps that pull in Nokogiri -- it gets compiled during staging and often that causes a lot of memory usage.
Disclosure: I work for Pivotal, we do the majority of Cloud Foundry engineering. We also sponsor Spring.
[0] https://www.cloudfoundry.org/just-released-java-buildpack-4-...
[1] https://github.com/cloudfoundry/java-buildpack-memory-calcul...
Thanks for the links. It's good to see that there is ongoing development to improve the situation.
It would still be nice to be have a Spring Boot app work on a 512MB container but even pretty simple ones don't seem to.
It would still be nice to be have a Spring Boot app work on a 512MB container but even pretty simple ones don't seem to.
There must be more we can do, but I honestly don't feel qualified to say what it is. Ben Hale is the fellow to ask, he's the JBP maintainer.
I've recently toyed with the idea of taking libbuildpack and OpenJ9 and just ... seeing what I can do. But I'm ill-qualified to tinker with either and it's in the pile of fifty kerjillion other sideprojects I want to do.
I've recently toyed with the idea of taking libbuildpack and OpenJ9 and just ... seeing what I can do. But I'm ill-qualified to tinker with either and it's in the pile of fifty kerjillion other sideprojects I want to do.
You mentioned Dropwizard early on, in my experience I have found it to be the polar opposite of Spring.
Where Spring is an "everything but the kitchen sink" framework, Dropwizard is just a collection of best-in-class libraries that are easily swapped out if you prefer something else.
I don't get to do so often professionally, but if given my choice of tools ill generally opt for a combination of Dropwizard in Kotlin.
Where Spring is an "everything but the kitchen sink" framework, Dropwizard is just a collection of best-in-class libraries that are easily swapped out if you prefer something else.
I don't get to do so often professionally, but if given my choice of tools ill generally opt for a combination of Dropwizard in Kotlin.
One big drawback of Dropwizard (at least for us) was that it was very problematic to deploy it as a war in a tomcat environment. There is wizard-in-a-box but there were a lot of issues with that as well.
Yeah, that's definitely a square peg + round hole problem. Dropwizard is intended to be deployed as a "Fat Jar" and does not need tomcat/tomee.
This is nice because it makes it easier to treat your servers like disposable cattle when (almost) all of your configuration and dependencies live in your easily deployed Jar.
This is nice because it makes it easier to treat your servers like disposable cattle when (almost) all of your configuration and dependencies live in your easily deployed Jar.
Well, if you're doing microservices you're usually nullifying most of the benefits of this kind of architecture if you're just deploying them on war files on a single application container.
For me dropwizard looks like what you'd get from a room if experienced Java guys picking the best of breed to do one thing and one thing well.
Spring boot feels like it was from a room full of people where there's a guy in the corner with a form of tourettes that makes him keep yelling "Spring! Take the Spring option!"
It just isn't always the best option and sure, you can often switch out for something else but that defeats the point of an opinionated collection of the best available choices.
Spring boot feels like it was from a room full of people where there's a guy in the corner with a form of tourettes that makes him keep yelling "Spring! Take the Spring option!"
It just isn't always the best option and sure, you can often switch out for something else but that defeats the point of an opinionated collection of the best available choices.
If you think Spring could make better bundling choices, tell them. They are very open to feedback.
And if they don't qualify as "experienced Java guys" then I don't know who can, short of Gosling.
And if they don't qualify as "experienced Java guys" then I don't know who can, short of Gosling.
Agreed. Kotlin + Dropwizard is an interesting approach. How well do Kotlin and Jersey play together in your experience?
Wonderfully, no complaints so far.
You should add the Jackson Kotlin module so you can pass Kotlin data objects around: https://github.com/FasterXML/jackson-module-kotlin
This combination has made me as productive as I've ever been.
You should add the Jackson Kotlin module so you can pass Kotlin data objects around: https://github.com/FasterXML/jackson-module-kotlin
This combination has made me as productive as I've ever been.
Pretty good article but I wish we had the source code so we could compare code complexity also.
The primary reasons for choosing a particular language for your application server usually come down to developer ergonomics, developer availability and library availability / integration for your specific domain. Performance rarely comes into it; performance while scaling into astronomical request numbers is important for top web sites, but most app servers don't see that kind of load.
Even if some requests needs crunchy CPU power, it's better to offload them into something asynchronous than try really hard to make them perform well enough to be synchronous. Typically, hefty CPU jobs come in varying sizes, they're rarely guaranteed to be runnable under the 200ms or so latency bar for synchronous requests.
Even if some requests needs crunchy CPU power, it's better to offload them into something asynchronous than try really hard to make them perform well enough to be synchronous. Typically, hefty CPU jobs come in varying sizes, they're rarely guaranteed to be runnable under the 200ms or so latency bar for synchronous requests.
I find that laughably generous. In my experience, Java gets a pass because it's "enterprise", whatever the hell that means. I've never heared anyone make a compelling case for Java on technical merit. It's always "we're a Java shop, because we're enterprise".
"I've never heared anyone make a compelling case for Java on technical merit."
IMO this is a sign that you should expand the company you keep rather than being indicative of any flaw with Java.
IMO this is a sign that you should expand the company you keep rather than being indicative of any flaw with Java.
Because you can find libraries for all the "Enterprise" technologies easily. Besides .net, not many ecosystems offer that kind of library support. From XML signatures, to pkcs11, to complete soap support (including ws-security), to many others.
Fact is, in the Enterprise you'll have to interface with many of the aforementioned technologies, and Java still has the most support for them. We find that even in .net we sometimes have to implement some things on our own from the horribly convoluted "Enterprise" technologies because a specific feature isn't supported.
Fact is, in the Enterprise you'll have to interface with many of the aforementioned technologies, and Java still has the most support for them. We find that even in .net we sometimes have to implement some things on our own from the horribly convoluted "Enterprise" technologies because a specific feature isn't supported.
If you're a business making a language choice based on the technical merits of the language itself, you are very much doing it wrong.
1,000 requests per second for a hello world micro service is horribly slow. I don't know what architecture they are using bit ~100,000 / CPU for simple requests is completely reasonable making this test very dubious IMO.
Some of the stacks he tested had significant failure rates at 1000/sec though.
Bumping it up would have made the comparison less interesting.
Perhaps it was just a small VPS?
Bumping it up would have made the comparison less interesting.
Perhaps it was just a small VPS?
One issue here is that it’d really be more appropriate to run the test twice and take the second result. This should get most JITing out of the way.
It’s hard to be sure what’s happening given the lack of source code, but 1000 requests per second where the request doesn’t do much is a fairly minor load for a well-written java service on modest hardware. I would expect the ‘lightweight’ java example to do better, assuming it’s just jetty or something.
It’s hard to be sure what’s happening given the lack of source code, but 1000 requests per second where the request doesn’t do much is a fairly minor load for a well-written java service on modest hardware. I would expect the ‘lightweight’ java example to do better, assuming it’s just jetty or something.
Hi All, this has received an incredible amount of views and comments since I posted this and left the house!
I appreciate the feedback comments! I'm very much still playing around with different technologies and writing about them as I go, this is more a learning experience for me that I've documented and I would take what I'm saying with a pinch of salt.
I thought I'd also clarify that I'm using the code/docker images that I created in the previous article as the base from which I'm running my tests as that seems to have gotten missed by a few peeps!
I appreciate the feedback comments! I'm very much still playing around with different technologies and writing about them as I go, this is more a learning experience for me that I've documented and I would take what I'm saying with a pinch of salt.
I thought I'd also clarify that I'm using the code/docker images that I created in the previous article as the base from which I'm running my tests as that seems to have gotten missed by a few peeps!
I definitely missed it. Maybe adding a link to this one as well would be helpful.
Edit: I see the code using the `com.sun.net.httpserver` package, but not the Spring Boot version.
Edit: I see the code using the `com.sun.net.httpserver` package, but not the Spring Boot version.
How does an "Hello world" request on localhost take an average of 50~100ms using any framework ? 1ms would already be too much. Something seems way off with this benchmark.
The myth that java is slow is not a myth it is true for medium to big programs with lots of interconnections, because with the abstraction you loose control on the program behavior.
You gain in other things, like abstraction, but the penalty is enormous. We use very high level languages in house, but when we do it performance is not the priority.
Doing "Hello worlds" is not a valid debunking of anything because , guess what? printing a Hello world in a screen is a very simple operation.
We have millions of lines of code and we have done tests on just converting 20-30Ks of our c,c++ code to java and the result has been disaster: Hundreds or thousands of times slower. That's right.
In my opinion if other companies are deluded wanting to be lazy, much better for us as competitors, but children should not be intoxicated with bad advice.
My advice is do not believe me or anyone else, when in doubt just test on your own.
You gain in other things, like abstraction, but the penalty is enormous. We use very high level languages in house, but when we do it performance is not the priority.
Doing "Hello worlds" is not a valid debunking of anything because , guess what? printing a Hello world in a screen is a very simple operation.
We have millions of lines of code and we have done tests on just converting 20-30Ks of our c,c++ code to java and the result has been disaster: Hundreds or thousands of times slower. That's right.
In my opinion if other companies are deluded wanting to be lazy, much better for us as competitors, but children should not be intoxicated with bad advice.
My advice is do not believe me or anyone else, when in doubt just test on your own.
Like with any language, the level of abstraction is up to you... one could just as easily "lose control" with C++.
Hundreds or thousands of times slower Java? Have you considered that the conversion was done with a weak mastery of the language or runtime?
The HFT folks working in Java would be taken aback to learn the language doesn't work.
Hundreds or thousands of times slower Java? Have you considered that the conversion was done with a weak mastery of the language or runtime?
The HFT folks working in Java would be taken aback to learn the language doesn't work.
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