What is the best dynamic language to pair with Java on a large Java project?
We are considering using a dynamic language for tests, controllers, services. Some options are Groovy, JRuby or Jython. What are the pros and cons of each for this? Ideally we'd be able to call Java from the dynamic language as well as call the dynamic language from Java.
EDIT: If it helps, we're using Hibernate with PicoContainer and Webwork.
Thanks,
Alex
There are really three dynamic languages that offer a very seamless interop with Java - scala, groovy and clojure. From there, I'd ask your team which language they would rather work in or have them try a prototype in each language and see what they think.
If the team efficiency isn't important in the beginning, look to what problem each language attempts to solve:
Groovy is going to be very loose but natural to experienced Java developers and allows fast prototype development due to it's duck typing.
Scala is going to enable you to write DSLs making it a good for frameworks and tools where you want to solve the problem in a language more akin to how you would describe the problem.
Clojure is going to impose lisp's functional programming and immutable state concepts and could be a very natural fit for problems in AI, natural language processing, etc.
Finally, I've gone down the path of looking for the perfect language to base projects on and have found there is no perfect language. All of the languages I've mentioned above compile to native JVM byte code and are quite solid. Sometimes you just need to pick a language that might not be as cool as the others but gets you on the way to solving your problem.
I recommend Groovy, principally because it interoperates seamlessly with Java, and is almost a superset of Java, so very easy for a Java developer to learn. I have absolutely no evidence to support this, but based on hearsay, guesswork, and personal experience, I suspect the Groovy community is much larger than that of either JRuby or Jython.
Incidentally, Groovy++ is way too immature to consider for production use, in my opinion.
The answer is, of course, going to depend somewhat on matters of taste and flexibility. If there are folk who don't have experience with Ruby or Python then Groovy is going to have a syntax much closer to Java (in fact it is a superset of Java), and consequently be a much easier sell.
I can't really speak to JRuby as I haven't used it.
Groovy gives you probably the easiest interop with Java of the three you listed. It also has a very nice BDD library in EasyB which I like a lot. On the negative side I don't think the features or syntax of Groovy really hang together very well. It can kind of feel like a whole bunch of separate extensions to Java.
Jython is of course Python so the syntax is different, but also has all the consistency of Python. Interop is very good at the script level but at least used to be a bit awkward if you wanted to write pre-compiled classes in Jython that you call from Java. The other main pro over Groovy for me is that is that you have a real REPL to interact with the Java project.
I would also mention Clojure, the syntax is even more different but the Java interop is excellent, probably the best of all, and again you have a REPL. On the down-side if folk have trouble adjusting to Ruby or Python syntax then a Lisp is probably right out.
Clojure is probably the best dynamic language for controllers and services. (depending on what you mean with "services".
Scala and Groovy++ has the best java interop, but those are not dynamic (well in Groovy++ you decide for yourself what is typed.). Scala has the look and feel of a dynamic language. Scala has good testing frameworks http://www.scalatest.org/ and Specs and AKKA is very mature for services and also has Java APIs
I'd suggest going with Jython. The syntax is clean, and you get whatever additional power/conveniences that Python gives you.
For example, if you were to go with Groovy, you are basically limited to only what Java will give you. Jython would add the powers of Python to that as well.
If it helps any, I've used Jython with Hibernate, SOAP, Corba, and EJBs and it is much easier than doing the same with just plain Java.
Related
There is some hype with languages like Python (that I like very much) and Ruby but I was writing a medium-size system in Python and feel the lack of some tools that I would have if I was using Java: Eclipse features, JUnit integration and some language-features like catching some errors in compile time.
Some people says that Java is dead as a language. But large important software are written in Java: Hadoop, Lucene and many others.
Is Java a better language than Python or Ruby for medium/large infrastructure software like these?
This kind of question can get very argumentative... For enterprise software most of time the key factor is political, not technical.
If you own the business, stick with the technology that best fits your vision. If not, use Java - it is politically safer.
On the technical field, it is almost a tie.
You make a valid point in saying that Java is more suited to enterprise software. That's really where Java shines: it works very well for enterprise programming.
However, your gripes about the tools in Python and Ruby are unfounded. PyDev for Eclipse takes full advantage of the same features that you would enjoy if you were developing in Java. Ruby has a similar plugin for Eclipse. Unit testing frameworks like pyunit, nose, and others exist for both languages (and I believe PyDev has support for unit tests). Also, just like a Java compiler would catch an error at compile time, a Python script will give syntax errors before you run it, along with an (IMO) much more understandable error system than a Java compiler.
Since Python and Ruby are scripting languages, their area of expertise lies more in small tasks, rapid development, and using frameworks like Django or Rails. So yes, more heavy-duty languages like Java are great for enterprise, but there's something to be said for the elegance and ease of use of Python and Ruby.
All much of a muchness really. There are features in Python/Ruby that your aware of that make them a more appealing offering than say Java. Static typing can be your best friend most of the time, and a pain for the other.
Lack of tooling is related to adoption. Java/c# has a larger adoption.
Corporates/Enterprises and medium to large organizations, like to procure solutions with contracts as opposed to technical merits.
From experience Python does have some speed issues, I can't comment on Ruby, but I imagine that if your applications require dedicated speed I would not use python.
Also threading and multi-core processing is not as good as it could be in python, although 2.7 seems to improve a lot of the old problems, I think the GIL problem still remains for threading.
My only comment on Java is that it now has Oracle behind it, and depending where your sitting and how you like Oracle, might change your attitude to Java. especially if your designing for Open Source solutions.
Of course I'm not talking about using Clojure just because I can.
I'm curious about where/when to use Clojure and what is the value it brings to a project.
Suppose I'm doing Java web development, where I can use Clojure? any use cases are in your mind?
Thanks.
I'm a long time rubyist and I believe that I'm far more productive in a dynamic language that has good facilities for interactive development (i.e. a repl).
Clojure gives me this productivity benefit while offering much better performance than ruby, better concurrency features, and does not require crossing a bridge of any form to interact with java libraries. It can also be compiled into java classes so I can make libraries for java people without them needing to know or care that it's clojure and not java code they are running.
I may be posting a premature question, and maybe I'm just freaking out for no reason, but the way Oracle is handling Java is not very promising. I am a nerd who fell in love with Java from the first sight, and use it all the time in my personal/freelance projects but now I am thinking of a replacement.
I am fluent in C#/VB.NET too but I am looking for something more like:
Open Source
Compiled
Cross-Platform
Object Oriented
Large standard library
Extensive documentation
Web development is a major plus
I was thinking about a compromise: Python/Django for web development (or PHP), and Qt for thick client development. Anyone with better thoughts?
Not so long ago, I decided to explore away from the JVM. I set foot on python, and even though i'm nowhere near the expert/ guru level, I dont regret it. Didn't choose C# (considered it) because I consider it to be more of the same. I alredy know (and like a lot) C++, so python seemed like something new, which is what I was looking for.
It fullfils many of your requirements. Particularly, i'm decided not to learn PHP, so the web frameworks in python came in great.
Not to mention, Python has a large community (also see here), always eager to help and teach, which I consider to be very important.
Just my two cents.
Might be worth loking at the other JVM languages - Clojure and Scala are the two I personally think are most promising.
Yes you are on the JVM, but you're pretty independent from Java the langauage and don't have to use any Sun/Oracle implementations if you don't want to.
Having said that - I think that you are worrying a little too much about Java, too many players (including Oracle!) have too much invested to let it go too far off course.
Try Scala. It looks extremely elegant and promising. Being object oriented and sharing a lot with java in a very concise manner.
Everything you said points to C#, except for the Open Source point.
To fix that, there's Mono.
You could try D. My one-sentence description of why it's an awesome language is that its generic programming/compile-time introspection/template metaprogramming facilities are good enough to give you almost flexibility of a duck-typed language, while its execution speed and static type checking rival or exceed C++ and C#.
I think it meets your requirements quite well.
Open source: The frontend to the reference DMD implementation is open source (the back end isn't due to restrictions beyond the author's control). Work is underway to glue the reference frontend to open source backends such as LLVM (LDC) and GCC (GDC). In the case of D1 (the older version of the language) the LLVM port is fairly mature.
Compiled: D is meant to be compiled to native machine code, i.e. raw, inscrutable hexadecimal numbers.
Cross-platform: The reference DMD compiler supports x86 Windows, Linux, Mac OS X and FreeBSD. GDC and LDC will likely support a lot more CPU architectures.
Object oriented: D isn't a "pure" OO language in the Ruby sense of everything being an object, or in the Java sense of not supporting any other paradigm. It does, however, fully support Java-style OO as a subset of the language, along with procedural and functional style programming.
Large standard library: D1 has Tango, which qualifies. D2 has Phobos, which is not "large" yet by modern standards but is larger than C or C++'s standard lib. However, recently there has been a large interest in contributing and Andrei Alexandrescu (its main designer) has accepted several new contributors, including myself.
Extensive documentation: The standard library and language are reasonably well documented at the Digital Mars website. There's also Andrei Alexandrescu's book "The D Programming Language".
Web development: This is an admitted weakness. D doesn't (yet) have a good web framework, though its native unicode support and excellent generic programming support should make writing one relatively easy.
I too would like another Java-like technology to come along. Lately I've been doing Flex/Actionscript. While I really enjoy it, Actionscript technology seriously lacks the elegance that Java has. Adobe can write some good cross platform APIs, but they just don't have the head capital to build elegant languages and compilers. I've also tried Ruby, but the VM for Ruby is really bad. I've gone back to Java after my flirtation with other technologies and I think it's because the language is good enough, but the JVM is by far the best out there.
So do you want to stay with the JVM or do you really want to the leave the JVM altogether? Staying on the JVM there are lots of options: JRuby, Scala, Groovy, Javascript, Clojure are the big players. However, there are tons of great languages that can take advantage of the JVM's features.
Leaving the JVM there are still good options like python, ruby, and erlang. But you give up some of the nice features of the JVM like performance (big one), and the ability to drop down to a nice language like Java if you need speed. Those others mean using C or nothing at all.
I finally stopped worrying about Java's future. Sun did all it could to screw it up and it still turned out pretty darn good. I think Opensource has a lot more influence over Java's success than Oracle or Sun could ever have had.
I can't post comments yet, so I'm posting an answer related to the Python discussion. Though Python isn't compiled to machine code, there is a Python-to-C compiler called Cython, which can compile nearly all valid Python -- closures are finally (!) in the latest development release. It's have a big impact on some parts of the Python commmunity, e.g., I was at Euroscipy recently, and over half the talks mentioned Cython.
I personally don't like PHP, but it does meet all of your requirements. It doesn't officially support compilation but there is the Hip Hop project which compiles PHP to C code. Facebook is currently heading up this project.
That said, I highly discourage you from using it :)
C# is the only thing that will meet your needs and not feel hopelessly archaic, or frustrate with limited library. For open source/non-windows, use mono. It's a good, mature implementation of most of what's important in the CLR.
Some things (WPF, WCF, etc) are "missing" from mono, but these aren't so much part of the platform as they are windows-specific proprietary toolkits. Some of them are being implemented slowly in mono, some aren't. Coming from java you won't miss them because you're looking for a platform and good standard libraries to build upon, not a gui toolkit or whiz-bang communication framework.
As far as a platform to build stuff with that's "like" java and offers similar levels of functionality, C# + CLR is the clearest option.
Using also Cython you get the best of the two worlds , the ability to code in python , the ability to code in C and C++ and of course compile your code and the ability to use both python a c/c++ libraries out of the box. And if you dont like C++ syntax , cython syntax is python syntax and more.
link text
Is it possible for a developer to use Scala without knowing Java?
Is it possible for a developer to use Clojure without knowing Java?
Note: For example I am a C# developer and I use .NET without knowing any VB (Of-course WF 4.0 uses VB for statements, so I refuse any projects involving WF 4.0 :) ).
Summary I: Thanks to all for your answers. Now I can tell one can use these languages without knowing Java (The Language). Now I've got another question: How can one start with Java (JVM) ecosystem? What are beginner, intermediate and advanced knowledge-bases (bags!)? To be honest Java ecosystem was always a bit confusing to me, so it would be very helpful to provide some "reference references" and "defacto tutorials" for learning (curve!) JVM.
(OK! I will post it as another question!)
Scala, and Clojure even more so, are totally different languages from Java. The only thing they have in common is that they run on the Java virtual machine. You do not need to know the Java programming language to program in Scala or Clojure. It would be useful, however, to know something about the Java ecosystem (the Java virtual machine and runtime environment).
Sure you can. You'll lack the knowledge of the standard library at first, but that's not a big problem when you're starting with a new languages anyway. Clojure & Scala, however, put a heavy emphasis on the Java interop and do not try to hide the raw Java stuff, so you'd probably have to learn more about Java(not the language - the Java Platform) at some point to make maximum use of the language and the underlying platform.
Speaking from the perspective of knowing Java and Clojure (but not Scala), you can use Clojure just fine without knowing Java. You have access to the core language, which is fully-featured, and libraries (e.g. clojure-contrib).
However, one of the big benefits of using Clojure (versus other lisps) is access to the Java ecosystem - libraries, debuggers, JVM, etc.
So, yes you can use Clojure effectively and I wouldn't let a lack of Java knowledge hinder you, but you'll add to your bag of tricks if you eventually start to learn enough Java to take advantage.
Well, Clojure has been ported to the CLR. Probably easier thant the whole jump to the JVM since you are a .NET developer. :)
http://github.com/richhickey/clojure-clr
yes, thats me!
Has not been much of a problem for me except for when I needed a stupid simple swing gui. thats when I had to go back and review java.
Scala is totally different language than java. So yes, you can of course use scala without knowing java ( but of course you have to learn scala first). Even though, knowing java (or any OO language) + some functional language makes it easier to understand scala.
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Me and some friends are writing a MORPG in Java, and we would like to use a scripting language to, eg. to create quests.
We have non experience with scripting in Java. We have used Python, but we are very inexperienced with it. One of us also have used Javascript.
What scripting language should we use?
What scripting language should we not use?
I'm responsible for a fairly large hybrid Java/Jython system. We use java for core API development, then wire Java objects together using Jython. This is in a scientific computing environment where we need to be able to put together ad-hoc data analysis scripts quickly.
If I were starting this system from scratch today, I would not choose Jython as the scripting language. I like Python fine, but I frequently encounter awkward mismatches between the Python type system and the Java type system. For example, if you just want a hashtable, should you use a Python dictionary or a Java HashMap? The decision might be different depending on whether you are just using the data structure locally in Python code or passing it across the Java boundary. Jython does a certain amount of type coercion for you, but it's not perfect. It's annoying to even have to think about issues like this when the purpose of using a scripting language in the first place is to enhance your productivity.
I assume JavaScript or JRuby would have similar issues. Today I would choose a scripting language that is specifically targeted to the JVM and leverages the Java type system. The obvious candidates are Groovy and Beanshell; Groovy seems to have been picking up momentum lately so I'd look most closely at it.
I agree with Viktor's Jython suggestion. Other than that and JavaScript (which you've mentioned, and is built into Java 6+ via the javax.script package), Groovy and JRuby are also worth looking at too.
By the way, you should look at Wyvern, also an MMORPG written in Java and using Jython for scripting. Steve Yegge, its author, has much to say about it from time to time. :-)
Java supports a variety of (scripting) languages, some are listed in Wikipedia here and here. You probably should choose language with powerful DSL and metaprogramming capabilities, such as Clojure.
But if you need something simpler, JavaScript might be a viable alternative.
How about Jython?
http://www.jython.org/Project/
what about creating your own specialized scripting language? If your app is written with java, you can use ANTLR (http://www.antlr.org/) to create your language parsing code.
The reason I say this is because a general purpose scripting language may provide too much power (because the script it to be used for quests only i assume).
But if making your own language is too hard then any of the above suggestions works - you just have to figure out how to bind the game's runtime into the script. I also suggest Lua (http://www.lua.org/) as another choice that lots of games use.
Short version
Don’t use a scripting language! Instead focus on configurability (which is something that a non-programmer can do well).
Longer version
One oft-used argument in favour of having a scripting language is that it allows for lesser programmers to more trivial tasks. Don't belive this, it will not save you any time, since trivial tasks are already accomplished by real programmers in no time. Aim for configurability instead of scripting, and you will have a much lower risk of bleeding over complex algorithms and concepts into the incapable hands of game designers. :)
Lack of hotswapping (edit-and-continue) would have been a reason to implement a scripting language in an MMOG (you don’t want to reload the whole game for a minor code change), but using Java, with built-in hotswap, you really have no reason for adding a scripting language on top.
I have spent years pondering these questions; in the day I implemented a complete scripting language, IDE, VM, debugger, etc for an MMOG myself. Since, I have grown wiser.
If you still choose to go down the infinitely crappy path of no return, keep the following in mind.
Pick a mature language which has been around for a while.
Auto testing, debugging and editing will suck bigtime until you make your own tools/plugins/start hacking around in the VM.
To date, I have never seen a DSL that improved the situation (getting a more maintainable product). Myself, I integrated Python into my indie game engine, but eventually came to my senses and ripped it out. "Stackless Python" is just a way of saying "unmaintainable but fast". Please, anyone correct me if I'm wrong?
See Java: Scripting language (macro) to embed into a Java desktop application
You have quite a few options:
Groovy - http://groovy.codehaus.org/
Jython - http://www.jython.org/Project/
JRuby - http://jruby.codehaus.org/
Possibly even BeanShell (http://www.beanshell.org/)
I'm a fan of Python myself so I'd recommend Jython, but they're probably all reasonable options.
I would have to recommend Javascript for this purpose. Mozilla Rhino http://www.mozilla.org/rhino/ is an excellent implementation that would fit your needs perfectly.
I recommend Javascript over Jython or JRuby because of familiarity. Trivial Javascript follows a very familiar syntax that anybody can use. However if someone wants to do something more intense, Javascript is a very powerful functional programming language.
I regularly use Groovy and Ruby professionally and believe that their purpose is best for writing parts of applications with particularly complex logic where Java is cumbersome to write. Javascript is a much better choice as an embedded, general scripting language to use in a game. I haven't used Python, but it's syntactically similar to Ruby and I would believe it's purpose would also be similar.
LuaJ seems to be a nice way to embed Lua into Java:
http://sourceforge.net/projects/luaj/
I am a big fan of Python/Jython due to the clean syntax - which may suit you if you have some python experience.
Otherwise Groovy which is based on Java syntax and may be an easier learning curve if most of your developers are Java guys. It also has the advantage of closer ties with the Java language and libraries.
Beanshell is good if you have simple scripting in mind - it doesn't support classes. However I don't think it has had any support over the last few years (the JSR seemed to kill it off...) so is perhaps a bad choice if support is important to you.