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Closed 10 years ago.
Edit:
English is not my native language. Maybe I am not expressing myself clearly enough. How about this:
The BCL for Oracle's JRE clearly states that the license is not applicable for java programs running on single purpose systems, such as TV set boxes or kiosks.
My guess is that there are some commercial kiosks and other types of single purpose systems that are running java programs, and I wonder what JRE's those programs are running on. I mean, statements like 'Amazon are using blablabla operating systems on their super big servers, with millions of users' makes me quite convinced that the blablabla OS is a good and reliable OS. In the same way, I would take comfort in hearing that 'Acme transport company are using IcedTea VM in are there ticket vending machines, and there are hundreds of them spread out all over the world'.
After searching and reading a lot, I am still having a hard time in understanding how well established the use of OpenJDK or some other completely free incarnation of the Java development kit and runtime really is.
Many developers do not seem to regard it a big issue if they run into problems compiling their software with OpenJDK, because they feel they can always switch to Oracle JDK/JRE if they have to.
But what if you really, really do want to build a commercial system based entirely upon free code?
Are there any critical systems out there that use nothing but IcedTea or whatever they are named, along with the usual bunch of third party libraries from Apache and others, that could help to convince me that using OpenJDK would not (edit) lead to a dead end?
Related
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Closed 10 years ago.
What are the cross-platform development principles in java? What problems are waiting me? I want to create cross-platform file manager (java se).
Technically Java only runs on one platform, the JVM. What you may have in mind is a cross operating system application. The most basic challenge is handling / and \ correctly.
However, the biggest problem you are likely to face is in the GUI providing a windows friendly interface on windows, mac friendly on mac and linux friendly on linux. This is an interface design issue rather than a coding issue.
You can get lots of articles on platform independency of java. Check this Oracle Documentiation on how java works.
You can go through this post how-is-java-platform-independent also.
So the key thing to keep in mind avoid doing platform specific things in your javacode
Do not execute OS Specific commands or scripts(you may be tempted to do that for things like checking disk space, but java has platform idependant implementation for that)
Avoid direclty depending OS variables(gettting home dir etc)
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Closed 10 years ago.
Intro
One of the coolest things about Java is that the JRE has a very small footprint as well as being highly portable, so I can run my application on nearly any platform with ease, and without having to integrate into the operating system linked libraries or C:\Windows\System etc - that is, the JRE can be run from within a folder.
.NET struggles in this regard - especially with size. Mono is becoming an ever popular choice but there seems to be too many dependencies that the Operating System needs to have.
Question
Are their any other RUNTIMES/languages (Perl, Ruby) that have this similar functionality that I mentioned above?
Again (1) Portability (2) Multiple OS support (AIX, Solaris, Linux) (3) Size for re-distribution over a network (4) Easy to Install and Deploy.
AIM
I'm looking for a light-weight run time or language that can be deployed on a server as easily as the JRE is.
For example: If I had to use Python, that would require added libraries to be installed on OS etc. Perl would be a good example, found on most Linux but endless hassle of for version and getting a third-party library.
ANSWER!!!!
This was CLOSED because it was thought to not be RELEVANT.
But FYI for those who this may help; outside of JRE, LUA is probably the most portable not requiring dependencies and compiles or system integration.
Ruby is not quite there, although it's default on most Linux (not on BSD)
BSD comes with Lua though :)
Lastly, Jruby is not practical, as it may use the JRE (20MB) and then JRuby itself (16MB).
Some thoughts for someone considering a deploy across multifarious "OS's" and being portable enough to distribute without consuming excessive bandwidth.
Thanks
JVM and .NET are only virtual machines, that interpret bytecode. There are a lot of language on top of them.
JVM
Java
Groovy
Scala
JRuby
Jython
JavaScript (Rhino)
Clojure
etc.
.NET
C#
VB.NET
Nemerle
J#
Boo
IronRuby
IronPython
etc.
There are another VM and script languages that can be run across the platform, i.e. Parrot that is Perl 6 VM or Lua that is X-platform script language (i.e. WoW use it). There are also project like LLVM (Low Level Virtual Machine) but this is still a little bit platform dependent.
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Closed 11 years ago.
I have a Delphi background, also C++ background. But last several years, I involved in web projects, and worked primarily with PHP. Now I am looking for a platform to develop simple desktop applications (interacts with server). I was thinking of Java as I am used with Eclipse IDE, and have C++ background. But I see Lazarus became a mature environment. its applications even work on Java Virtual Machine. In the past I have seen that some Amateur looking technologies have became popular than professional ones like PHP, Flash even Object Pascal. So should I choose Java, or lazarus for desktop application development.
If you have a C++ background, try the Nokia Qt framework which has everything you want to develop desktop application. the Qt SDK is shipped with its own IDE (which's really great) and rich APIs.
Enjoy :)
Of the two options, I would certainly choose Java (larger support base, more stable, more 3rd party libraries, etc).
You mention that you come from a C++ background. Why not just use C++ (theoretically easier than picking up a new language).
If Lazarus runs on the JVM, it should have access to the same libraries as every other JVM language, so you'd be learning swing, etc.
If you are going to do desktop apps and you want a decent GUI toolkit you really have two choices as far as I know, either go with a JVM language or .net
If you go with a JVM, why in specific Lazurus? There are dozens (well technically hundreds--possibly thousands) of JVM languages to choose from. Go with anything stable that helps you get the job done.
Hmm, that is UNLESS you don't work alone. If you work with others, I suggest Java (or C#) period (Maybe Scala). Otherwise you will have a heck of a time hiring and training.
There are also probably C++ GUI frameworks, even cross-platform sometimes but none will be as rich as everything that is available on the JVM or .net platforms.
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Closed 9 years ago.
I'm going to start building operating system and I don't know which programming language to choose for kernel. My favorite language is Java but I know that all major operating systems (Windows, Linux, Mac OS) is programmed in C, moreover Java requires virtual machine. Does it would be much harder to program than Java-based OS than C-based OS? What are the advantages and disadvantages of each of these languages?
http://wiki.osdev.org is an extremely useful site on that matter. It tells you how to build your toolchains, which language options that are available, and has some great example code.
Yvan
I would humbly suggest that you truly learn a programming language before trying to build an operating system, after which you would realize in which languages you can or cannot write kernels in yourself.
Programming languages such as Java simply does not offer the low-level routines necessary to create an os. You can implement your OS in c or c++. Unless you master bootstrapping code (read assembler) and a programming language such as c, it would be a good idea to reconsider a perhaps easier task.
You could however emulate an OS by running it as a program in another OS, in which case you may experiment with any language of your choise.
Does it would be much harder to program than Java-based OS than C-based OS?
How would you write the hardware-level programming to handle interrupts in Java?
There seem to be several Java-based OSs already out there. I don't know a lot about OS-programming, but there seems to be quite an extensive literature (altough a lot of it in German) about a Java-based OS called JX, from the University of Erlangen: http://www4.informatik.uni-erlangen.de/Projects/JX/publications.html
Maybe there is something there to help.
Writing a C-based OS should be the easiest, though, simply due to there being so much more information about it.
You won't be able to program an OS kernel in Java unless you have access to a compiler that will compile Java into machine language. Java requires a virtual machine which interprets the byte code and executes native instructions (that rely on the kernel). You must be able to interact directly with the hardware in order to program an OS which is something you simply can't do with Java. Your only option, really, is C mixed with assembly.
The JVM provides an awful lot of OS-like capabilities, and it can't be written in Java -- so either way, you're going to end up writing an awful lot of the code in C (or something that can produce code that doesn't require a virtual machine).
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Closed 10 years ago.
Is there a java library or framework (other than the javax.comm provided by Sun) that is easy to use when accessing serial and parallel ports ( especially RS-232 ).
I need something free that will work both on Windows and Linux.
The most common framework used for this is rxtx.
As andri pointed out RXTX is pretty much your best choice. There is an article on getting started with RXTX on Windows here (relating to RXTX 2.1).
If free isn't necessary -- remember, your time isn't free -- then Serial IO SerialPort might be useful. It's the only thing I found that works as-is on all of the following:
32/64-bit Windows
64-bit Solaris (didn't test 32-bit)
32 bit Linux (didn't test 64-bit)
Mac OS X
You do get source with the product, albeit with some weird and annoying build practices.
FWIW, I'm just a contented user, not affiliated with the company.
rxtx as the other posters have said. I've been using it and it works nicely. There is a problem if using nonstandard highspeed baudrates (multiples of 115200 e.g. 230400, 921600 are OK, but 1MB is not even if the hardware & underlying OS supports it), I've been told this will be corrected in rxtx 2.2.