I'm very new to scala and find many of its ideas very attractive. I've just discovered the scala for android project and I'm wondering if it could be expected to run well or perhaps even better than java?
Could it even be expected do some things better than java even if the processors are mostly single core in-order execution types at the moment?
If anyone has any example or experiences to share then please do!
The only "lag" would be the size of the apk, but if you use something like ProGuard it would represent only around 15k/25k more, nothing significant at all. As of performance, for what i've seen is the same. I mean, it is not worse (as happens with Clojure, being dynamically typed), but i think it's the same as Java.
Yes, it does. But to keep the package size down, use Proguard.
If you use SBT, there is already some plugin which automates the whole process.
As with most performance-related questions, the correct answer is 'It depends'. I'm no Scala expert (yet), but from what I've seen so far, it'll be future-proof - as in, build with Scala to get better / easier multicore support - as that's the trend that's rapidly popularizing, with dual- and quadcore processors quickly becoming commonplace in high-end smartphones. For single-core and 'simple' applications that don't really do much things that can be parallized, I'm guessing performance would be equal or worse. However, performance isn't everything, especially not for prototypes or one-off applications - ease of coding and development speed are more important, in which Scala, if you're familiar with it, can help (due to less code and smarter constructs).
Related
I'd like to write Intellij plugin and I wonder is it possible to do it in Go language? If so, what are my options; as pure go? as compiled to bytecode program acting as service and incorporated in plugin jar? Maybe something else? I want this to be fast and I hope it's not limited to JVM languages.
I'd like to write Intellij plugin and I wonder is it possible to do it in Go language?
As long as the language supports working with JVM it will be possible to do it. Otherwise no. As Go does not support this for now, the answer is no, you cannot.
So far I know of plugins written in Java, Kotlin, Scala.
I want this to be fast and I hope it's not limited to JVM languages.
In many many cases Java / JVM is just as fast if not faster then Go code. Keep in mind that the IDE is meant for being opened hours at a time and that gives the JVM a fairly good chance to optimize the code on-the-fly which can make it even faster than before.
For example the Go plugin for IntelliJ had a long standing problem with Delve (the Go debugger) as it was sending requests too fast to be handled in-order by Go and a special RPC implementation was needed in Delve. No other editors were this fast.
Coming from java/groovy/grails we are currently moving to rails. We have been having an abdolute blast with it. Testing has never been so easy and productive. And as a team we are convinced that we would like to move forward in this language.
We will be tackling some client solutions in pure rails soon.
This is not a what is better question. So please no responses advocating grails/django or whatever other technology.
The real question we would like to pose is an answer to the one nagging doubt that remains. As long time java developers coming from the JDK and the vast libraries you sort of feel that nothing is impossible, and its probably been done before in some framework. It's an empowering feeling that we slipped into over time.
We currently feel super expressive and productive in ruby/rails but we don't quite feel that sense of power yet. A sort of fear of problems to come. I'm not talking about scaling perse, but a fear that a potential client request is (undoable?).
I would really like to heard from any Java to Rails webshops (Or similar transgressions). Are there any pitfalls we might face, problems that we will have to tackle that we didn't use to before? A sort of heads up.
Furthermore, how easy is it to fall back on jruby? We are currently using plain ruby, and haven't explored that path yet.
to summarize, the road ahead looks exiting, and we will be diving into our first pure rails solutions soon. But It's also a little daunting and we're looking for some friendly advice from our predecessors.
note: once again, this is not about framework comparisons!
I can speak to JRuby and that it is easy to setup and use (especially for fall back Java code). Furthermore, it offers great performance and now 1.9.2 compatibility. The only issue you may run into is some of the C wrapper libraries not working. If you are looking to fall back, just be sure that you write extensive tests and you should be fine. If you want to try multiple Ruby interpreters check out RVM.
I want to migrate my entire C# 4.0(.Net 2010) desktop Application to Java.I don't know any tool available for that?Please suggest me good one.
Also, i would like to know what are the limitations and advantages of Cross Compiler for C# to java?
please guide me to get out of this problem...
Saravanan.P
Crosscompilers will usually produce rather messy code, and sometimes code that doesn't even compile.
Some (maybe most) will force your new code into having bindings with custom libraries from the crosscompiler, and thus be forever linked to that product.
Your new code will be very hard to maintain and expand as a result, and might well offer poor performance as well as compared to the old code when compiled.
In general, you would most likely be better off rewriting the application yourself (or hiring people to do so) if it is going to have to be used and maintained actively for more than a short, transitional period.
That said, for some things a crosscompiler can be helpful. For example start with a crosscompiled version and over time replace that codebase with newly written code, this would get you working more quickly and you'd not have to maintain 2 separate code bases, in 2 different languages, using 2 toolsets, at the same time.
I am learning Java.
I have learned and used Ruby. The Ruby books always tell the advantages of Ruby over Java. But there must be some advantages, that's why lots of people (especially companies) use Java and not Ruby.
Please tell the absolute(not philosophical!) advantages of Java over Ruby.
Many more developers experienced with
Java than with Ruby.
Many existing libraries in Java (That
helps JRuby too).
Static typechecking (can be seen as
advantage and as disadvantage).
Existing codebase that has to be
maintained.
Good tool-support.
More and deeper documentations and
tutorials.
More experiences with good practices
and pitfalls.
More commercial support. That's
interesting for companies.
Many of these advantages are the result, that the Java-ecosystem is more matured, than that around Ruby. Many of these points are subjective, like static vs. dynamic typing.
I don't know Ruby very well, but I can guess the following points:
Java has more documentation (books, blogs, tutorial, etc.); overall documentation quality is very good
Java has more tools (IDEs, build tools, compilers, etc.)
Java has better refactoring capabilities (due to the static type system, I guess)
Java has more widespread adoption than Ruby
Java has a well-specified memory model
As far as I know, Java has better support for threading and unicode (JRuby may help here)
Java's overall performance is quite good as of late (due to hotspot, G1 new garbage collector, etc.)
Nowadays, Java has very attractive and cheap server hosting: appengine
Please tell the absolute … advantages of Java over Ruby
Programmers should rarely deal in absolutes.
I'll dare it, and say that as a rule, static typing (Java) is an advantage over dynamic typing (Ruby) because it helps recognize errors much quicker, and without the need to potentially difficult unit tests1).
Harnessed intelligently, a strong type system with static type checking can be a real time-saver.
1) I do not oppose unit testing! But good unit testing is hard and the compiler can be a great help at reducing the sheer number of necessary test cases.
Reason #1. There's a lot of legacy Java code out there. Ruby is new, there's not so many programmers who know it and even fewer who are good at it. Similarly, there is a lot more library code available for Java than Ruby.
So there may be Technical reasons Ruby is better than Java, but if you're asking for Business reasons, Java still beats it.
The Java Virtual Machine, which has had over a decade of improvements including:
just in time compilation in the HotSpot compiler (JIT - compiling byte code to native code)
a plethora of garbage collection algorithms and tuning parameters
runtime console support for profiling, management etc. of your application (JConsole, JVisualVM etc)
I like this Comparison(Found on link Given by Markus!Thanks!)... Thanks to all... i am also expecting some more discrete advantages
And its Great!!
The language.
My opinion is that the particular properties of the Java language itself lead us to the powerful capabilities of the IDEs and tools. These capabilities are especially valuable when you have to deal with very large code-base.
If I try to enumerate these properties it would be:
of course strong static typing
the grammar of language is a LALR(1) grammar - so it is easy to build a parser
fully qualified names (packages)
What we've got in the IDE so far, for example Eclipse:
great capabilities of exploring very large code bases. You can unambiguously find all references, call hierarhy, usages of classes or public and protected members - it is very valuable when you studying the code of the project or going to change something.
very helpful code editor. I noticed that when I writing code in the Eclipse's java editor I'm actually typing by hand only names of calsses or methods and then I press Ctrl+1 and editor generates a lot of things for me. And especially good that eclipse encourage you to write the usage of piece of code first and even before the code is aclually writen. So you do the method call before you create the method and then editor generates the method stub for you. Or you add extra arguments to the method or constructor in the place when you're invoking it - and editor change the signature for you. And enev more complicated things - you pass some object to the method that accept some interface - and if the object's class do not implement this interface - editor can do it for you... and so on. There's a lot of intresting things.
There is a LOT of tools for Java. As an example of a one great tool I want to mention Maven. Actually, my opinion is that the code reuse is really possible only when we have such a tool like Maven. The infrastructure built around it and integration with IDE make feasible very intresting thinsg. Example: I have m2eclipse plugin installed. I have new empty project in the Eclipse. I know that there is a class that I need to use (reuse actually) somewhere in the repositories, let say StringUtils for example. I write in my code 'StringUtils', Eclipse's editor tell me that there is no such class in the project and underlines it with red. I press Ctrl+1 and see that there is an ability to search this class in the public repository (actually in the index, not the repository itself). Some libs were found, I choose one of them at particular version and the tool downloads the jar, configures my project's calsspath and I alredy got all that I need.
So it's all about programmer's productivity.
The JVM.
My opinion is that the JVM (Sun's HotSpot particularly) is a one of the most intresting pieces of software nowadays. Of course the key point here is a performance. But current implementation of HotSpot JVM explores very cutting edge ways to achieve such really great performance. It explores all possible advantages of just-in-time compiling over static, collects statistics of the usage of code before JIT-compile it, optimise when it possible virtual calls, can inline a lot more things that static compiler can, and so on. And the great thing here that all this stuff is in the JVM, but not in the language itself (as contrary with C# as example). Actually, if you're just learning the Java language, I strongly encourage you to learn the details of modern implementations of JVM, so you know what is really hurt performance and what isn't, and do not put unnecessary optimizations in the Java code, and do not afraid to use all possibilities of the language.
So...
it's all about IDEs and tools actually, but by some reason we have them for Java not for any other language or platform (.NET of course is a great competitor in the Windows world).
This has probably been beaten to death, but my personal opinion is that Ruby excels at quickly created web apps (and frameworks) that are easy to learn, beautiful to read, and are more than fast enough for web apps.
Where Java is better suited for raw muscle and speed.
For example, I wrote a Ruby program to convert a 192 MB text file to a MongoDB collection. Ruby took hours to run. And the Ruby code was as simple/optimized as you could get (1.9.2).
I re-wrote it in Java and it runs in 4 minutes. Yes. Hours to 4 minutes. So take that for what it's worth.
Network effect. Java has the advantage of more people using Java. Who themselves use Java because more people use Java.
If you have to build a big software, you'll need to collaborate. By having a lot of programmers out there, you are sure that there will be someone that can be asked to maintain your software even if the original developers have left the company.
Static type checking and good Java IDE offer no magic and this is good for a lot of maintainer instead of Ruby.
It is not sufficient to indicate that java is statically typed and ruby is dynamically typed.
Correct me if I'm wrong, but does this cover the fact that in ruby you can add to and even
change the program (class definitions, method definitions etc) at runtime? AFAIK you can have dynamically typed languages that are not "dynamic" (can be changed at runtime).
Because in Ruby you can change the program at runtime you don't know until you've actually run the program how it is going to behave, and even then you don't know if it will behave the same next time because your code may have been changed by some other code that called the code you're writing and testing.
This predictability is, depending on the context, the advantage of Java - one of the contexts where this is an advantage is when you have a lot of developers of varying skill levels working on a fairly large enterprise application.
IMHO, what one person considers an advantage might be a disadvantage for someone else. Some people prefer static typing while others like dynamic. It is quite subjective and depends largely upon the job and the person doing it.
I would say just learn Java and decide for yourself what its strong points are. Knowing both languages yourself beats any comparisons/advice some other person can give. And its usually a good thing to know another language, so you're not wasting your time.
Negatives for Java:
There is a lot of duplication in libraries and frameworks available for Java.
Java developers/communities tend to create over complicated solutions to simple problems.
There is a lot more legacy in Java to maintain.
Too much pandering to business users has introduced cruft that makes middle managers feel better. In other words, some philosophies in Java are more concerned with BS instead of getting the job done. This is why companies like to use Java.
You'll generally need to write more code in Java than Ruby.
It takes a lot more configuring/installing/setup to get a fully working Java development environment over Ruby.
Positives for Java:
Speed.
Documentation.
Lower level language than Ruby, which could be a good thing or a bad thing, depending on your needs.
None of my points are very scientific, but I think the differences in philosophy and personalities behind Java and Ruby is what makes them very different to each other.
Better performances
There are more choices:
Developers - lots to hire
Libraries - lots of wheels already invented.
IDE's - lots of development environments to choose from. Not only just vi/emacs + a shell.
Runtimes - if you for some reason do not like the JVM you use on the system, you can either download or buy another implementation and it will most likely Just Work. How many Ruby implementations are there?
Please note that this has nothing to do with the LANGUAGES as such :)
Reading up on this : Is Ruby as cross-platform as Java? made me realize at least one factual advantage of java over ruby:
The J2ME-compatible subest of java is more portable than ruby
as long as JRuby won't run on J2ME which may be forever
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This is half rant, half question.
Is it worth using Grails? I'm trying to develop a relatively simple database-driven web application. My expertise is in Java, so naturally Grails seemed like a good choice. At first I thought of using Spring, JPA and Hibernate, but I’ve used that previously and have run into all sorts of tedious configuration and coding work. Grails advertises itself as solving this.
My biggest frustration with Grails is all of the little things that don't work. What I mean is that it doesn't work as one would intuitively think it should. It's very rough around the edges. I run into problems constantly. Sometimes it's my lack of Grails understanding — other times I've discovered legitimate Grails bugs.
One major issue is the lack of good Eclipse integration. There is a Groovy and Grails plugin, but it doesn't do much other than syntax highlighting. Calling Groovy from Java and vice versa is very painful to configure. Not having good IDE support is a major bummer.
What happens is I sit down trying to develop my web application. At the end of the day I realize that I've spent about 85% of the day debugging Grails-related issues. If it isn't Eclipse problems then it's eager loading, fetching in the view, one-to-many relationships, weird empty file bug behavior, a weird property/getter bug — it just goes on and on. This is just a sample of the issues I ran into today. My last sit-down with Grails yielded a whole bunch of different issues.
I sometimes wonder if it's worth it. I'm curious if others have experienced this. Are there people actually using Grails to productively crank out a web application? Are there other frameworks for rapid web development that I should be considering?
We had a team of 12 people all seasoned senior Java devs who learnt Grails from 0.6B and we are all still working on projects based on Grails. I wouldn't go back to Java willingly, and we are all relieved to have broken the back of how to get somewhere quick with a Grails app.
It was a struggle, it was not easy and there was/is frustration.
Nevertheless we delivered something very quickly given our ongoing efforts.. There are bugs, many which have workarounds.
I have heard of several instances of developers who are good at Java trying to dive into deep, complex incantations of Grails projects. We eschewed all Java and went pure-Grails and Groovy. We made sure we started simple, built up the complexity as manageably and as practically as possible.. We dared not dive in the deepest end and hope that our Java knowledge was enough to carry us.
We had eventually created something huge and complex that worked fabulously and did so far faster than writing pure Java/Spring/Hibernate version; and thats without decent IDE support and a far worse situation in terms of bugs than today.
As regards Eclipse support, the only real IDE to use for Grails/Groovy is Intellij - the Eclipse support is way behind, sadly: I was an Eclipse lover and am far from being an Intellij convert - the Grails/Groovy support blow everything else away though.
Yes, Grails is immature compared to Spring perhaps. Or Hibernate. And I would wager that in the first 1.5 years of their existence they were equally as fraught with issue.
That being as it is, places the onus on you, to take care that you keep complexity to the absolute minimum, to carefully test-first (in our opinion) and build up to complexity gradually and with care.
There is no fast code solution with Java once you involve Spring/Hibernate in the stack. The complexity Grails embodies is a reflection of Spring's / Hibernate's own complexity. If you feel that you time is better spent doing it with pure Java, I wouldn't argue otherwise.. I still have my WTFs but now that the steep learning curve is behind me I think I will stick w Grails some more.
I very much enjoy writing grails application for two reasons:
I don't have to use Java
I can use Java
I think after having become familiar with grails one gets his things done very quickly and elegantly.
So much for the plus side. The minus side is performance, which hits me on two aspects: deployment and testdriven development.
I haven't managed to run more than 3 grails applications on a single (rented) server, because I quickly hit the memory and performance limits. There are simply too much frameworks included.
Plus, the testrunner of grails isn't worth that name. When I run unit tests, they should be done in an instant, not in 10 to 20s. So I find myself all the time writing business logic in plain java, because I can test it much faster. But I guess that this can be addressed with a better integration into the IDE (eclipse).
I think Spring's support of Grails is going to be a big boost. If anybody can move it past CRUD on the web, it's those guys.
I also think it's reaching a critical mass. There are several new books that will be hitting the market in 2009. I think those will help the adoption rate.
I fully agree with the original posters sentiments.
We are a Java + Spring shop and took the opportunity to try out Grails.
We first created a very small test application which turned out to be pretty simple to do and it worked pretty well. The main issues we had here were due to our lack of knowledge with Groovy and Grails.
Following this success (confidence boost) we decided we would attempt a slightly larger project. This has been a much more painful experience. As mentioned by others, we have uncovered all sorts of bugs and issues which were not immediately apparent on the surface. The app restart cycles get extremely painful and unless you have really good test coverage its a nightmare to do any sort of re-factoring.
Really frustrating is having code fail without a single error message! It just does not work and you don't know why?
I like the ease of use of plugins for JMS, Quartz and Remoting to name a few. Does away with a lot of tedious XML.
I almost like GORM for its simplicity though we have had several issues as well.
I don't like the loosely typed nature of Groovy and the fact that you have to run your application just to be able to catch a bunch of errors, reminds me too much of PHP or Rails.
At the end of the day we are asking ourselves if its possible to write a complex piece of manageable software using Grails...
We have a Grails application about to go into production....so we will see.
We are using grails + on the web layer + java with hibernate and spring on the service layer. It's the classic three layers (web, logic, data) where the web is grails and the logic is implemented in java. As is usual in java, we use bean objects that represents the data between different layers.
It works pretty well and it was the best solution for our case as the bean objects were already there, as well as the database structure. From our experience, I think grails has a great value as the web presentation layer, but I would stick with java to write the business rules and to persist the application data - as grails "is" java, all the grails-java integration is pretty straight-forward.
We use eclipse to develop the grails application and it's poor integration, as people said in here. But, as a suggestion from other developer, we run the grails application from the command-line and only use eclipse to save the source files, and it works pretty well, as the application is updated on the fly.
I yet don't feel comfortable for using grails in other places than in the presentation layer.
I have a lot more experience with Ruby on Rails than I do with anything in the Java world, so I'm coming in from a different perspective. Overall, Grails is much more rough-around-the-edges than Rails is, partially due to its immaturity, and partially because it relies on two insanely complex frameworks under-the-covers (Spring and Hibernate). Rails also has a much bigger community.
But, Groovy as a language has made huge strides, and is a pleasure to work with. Thanks to the improvements made in Groovy 1.6, Grails is quite a bit snappier than JRuby on Rails, and you get amazingly good XML support via GPath. There's a lot of nice features you get by being on the JVM (like concurrency and tons of threadsafe code), but without having to muck about with Java (a language I don't much care for), so I'm having a really hard time of convincing myself to use anything on MRI.
Python is looking tempting, though, I must admit.
As for your Eclipse problems, I can't help. I use Vim and Emacs, mostly because I can't stand using IDEs. For dynamic languages like Groovy, Ruby, and Python, though, I don't think IDEs really introduce any real benefit, as there isn't really any place for code generation, or a need to compile. Maybe try working sans IDE for awhile and see if things are smoother?
So, yeah, I think Grails is worth it. They've done a helluva job in getting things working as quickly as they have, and the Grails and Groovy teams are both really, really dedicated.
I am totally with you! Grails still feels so rough around the edges that it's almost a joke to compare it with Rails. If at least the error reporting was a little bit better. But I guess that's probably also due to the huge amount of libraries that it uses under the covers. One word: stacktrace! I am also not a big fan of the model->db approach (Rails has db->model). The scaffolding also leaves much room for improvements. Then "no restart required" also does not work as advertised. (I am not sure what's worse - having to restart all the time or sometimes finding weird behaviors that go away when you do restart) And don't get me started on GORM. (When it takes hours to find a way what would have been a simple SQL you start to wonder whether this whole ORM really saves you time) Maybe as long as it is simple.
I mean: it's still one of the better choices of a framework when you are coming from the java world. (So much useless crap out there that calls itself a web framework) ...it has potential. I just wish it wouldn't have build on top of so much other complex stuff.
Anyway - let's hope these things get sorted. At the moment I am lurking at playframework.org which also looks very slick and promising.
It will be worth it when they finish the eclipse plugin. The sooner the better I say. Trying to sell groovy to my boss isn't going to be simple until that happens.
I find that the biggest advantage of Grails is that I don't have to care about the database anymore - the schema is automatically created / updated, and the persistence is largely done for me (no more writing SQL queries). This is a huge relief. The other thing that is rather nice is that once you settled on the templates for controllers and views, adding new domain objects is pretty fast. Although I suspect that you will do ongoing changes for your views at least, back-fitting them to the existing ones.
As for the IDE - it seems that IntelliJ is the best option, but I'm happy using Netbeans 6.5. I use MyEclipse for all other development, but Netbeans just has better Grails support now.
I was an Eclipse user before I started using Grails. It was quickly apparent that wasn't going to cut it. So I tried Intellij and NetBeans. At the time Intellij was better as far as Groovy and Grails were concerned. However, NetBeans was free and that made it good enough for me. Since then all three have had new versions or new plugins released. I am still using NetBeans because of the cost of Intellij. With the acquisition of G2One by Spring Source one of the expectations is more support for Groovy and Grails in Eclipse. This will be necessary for increased adoption.
Using Grails for a new project is wonderful. So much of the Enterprise Java baggage is no longer necessary. I can imagine trying to port something would be difficult because until you understand where a framework strength's and weaknesses are it is hard to utilize it efficiently. It is promised that JSP support will come easier in Grails 1.1, I don't know if using a beta version while trying to grok a new framework is a good idea. The testing has also gone through a major revision for the new version. If time allows you may consider waiting as the 1.1 release should be very soon.
If you have an opportunity to give Grails a try in a different IDE when starting a project from scratch I think you will see it in a different light.
I have just started using grails on a new project...not having to write ANY xml files yet still have the power of Spring and Hibernate is truly amazing.
Use IntellijIDEA for the IDE though, I actually discovered Grails through the IDE (I might be biased though, I hate eclipse).
Totally. There are so many Java frameworks that the bar is set quite high for newcomers, and it's a testament to Grails that it was able to rise above in such a crowded space.
It still has a few edges that are sharp, but those are just a matter of time before they're matted down, the underlying project is VERY much worth it.
Grails might be to big for your type of application (based on the numerous files it created on the first initialization and the resources it takes). If you're looking for something simple, Grails might not be what you're looking for. If you are looking for something simple and works, so far I reckon django can do your job well. Take a look at how simple (how many files it requires) to create a CRUD apps from its tutorial. From here, your apps can (relatively) easy to scale as your needs and requirements grows.
I'm not sure they will ever be able to make Grails right you know. And by right I mean address all the details (small and big ones) which in the end makes it feel brittle and fragile. I'm not even sure that there is a real development team (meaning more than 2 people) behind it.
Every single time I iterate over a feature of my Grails projects, trying to improve something, it is the same workflow: everything falls apart, then it's a hundred of 'google' test cycles, then you find out the reason you can't do what you want and you do something else.
In the end, you're frustrated because you don't even want to touch anything that runs. And things that don't well, you drop them!
I'm considering a switch to Rails via JRuby. That may be the best of both worlds: a capable web framework with an active and large community, a dedicated team of developers, a platform which is not based on questionable and complex frameworks like Spring or Hibernate, a quick and ambitious release cycle. And JRuby because frankly, so many Java assets in my backpack, I can't just throw them away.
If your expertise is in Java as you say. You should have a look at Play Framework - it's a web framework inspired by Ruby on Rails with a very short development cycle - just save your Java source file and update your web browser. And if you want to try another language, Play Framework has a module that let you use Scala instead.
I like Play Framework since it's easy to understand and has good performance. You can also use JPA and Hibernate for the ORM-layer if you want.