Differences between JVMs in different JRE's - jvm

There are a number of JRE's(Suns, Oracles, ) with different JVMs (hotspot, IcedTea).
So are there any major differences between them all? Are they similar in that to linux distros where one will focus on security, another on usability?
Is there much difference in terms of speed between them all or are they more influenced by hardware?
I've tried to get some nice explanations or even examples of different JVM's but haven't managed to find much information. Any help appreciated.

You may find the blog post Understanding the various JDKs useful.
IcedTea provides webstart, plugin implementations, a build harness
(and more) for OpenJDK to help the various Linux ditros do their own
JDK builds. A typical Java Application Developer probably isn’t going
to use IcedTea, instead, they’d consume the JDK provided by their
Linux distro provider.

IMHO, There is not much difference between them as they are all based on OpenJDK to some degree or another.
The most significant difference is that JVMs are only available on specific OSes. e.g. On IBM AIX, you won't get the Oracle/Sun JRE.

Related

Hortonworks vs Apache projects

I want to know what is the difference between installing HortonWorks HDP vs installing the components directly from Apache projects? One thing I can think of is that Horton works probably has the packages aligned so that the version of each component is compatible with that of the others within the suite, while getting them directly from Apache projects, I may have to handle version compatibility myself. Is that correct? Is there any other difference involved ignoring the support subscription aspect of it.
Thanks.
There are a lot of differences between "roll your own" and using a distribution. Some of the most obvious include:
All of the various components and versions have been tested and built to work together - incompatibility between versions (e.g. Hive, Hadoop, Spark, etc.) can be a painful problem to sort through on your own
Most distribution providers, including Hortonworks, will bring patches in from unstable releases into stable releases, so even for the "same" version (e.g. Hive 1.2.1) you're getting a better release than vanilla - these can include both bug fixes and "safe" feature changes
Most distribution providers, including Hortonworks, provide some flavor of centralized platform management. I'm a big fan of Ambari (the one that comes with HDP), for example - it makes configuration and monitoring significantly easier than coordinating a vanilla install
I would strongly recommend against trying to deploy vanilla, unless it's just for learning and playing. HDP community edition is free (both definitions) and a major improvement over doing it yourself. My last deployment of HDP was entirely based on the community edition.

What is the difference between Lazarus and CodeTyphon

Firstly, I saw some topics about these two but weren't my answer.
I'm looking for a good FPC(Free Pascal Compiler) IDE on GNU/Linux.
There are some IDE's like Lazarus and CodeTyphon. I need suggestion to choose one of those.
I've tried Lazarus once but all windows was separated. It looks messy and not interesting.
I would like to know what are the distinguishes between these two ?
I would like to know advantages / disadvantages each of those. Thank you
CodeTyphon is a distro of Lazarus, like Ubuntu and Debian are distros of Linux.
CodeTyphon comes with a large package of components and plugins, that otherwise you would have to google and download and install.
CodeTyphon have their own idea what are stable versions and what are not stable yet for both of FPC (compiler) and Lazarus(IDE). Whether their assessment is better or worse than upstream's Lazarus Team's, I don't know.
What about one-single-window plugin, it is work-in-progress and it doesn't seems to me it is ready for production use, no matter would you get it as part of CT or download and add it to vanilla Lazarus. However maybe it better works on Linux than on Windows, I don't know.
There were however issues with code legality in CT grande bundle. It is widely believed that Orca (if I remember the name) violates copyrights of glScene/vgScene, which also happened in early Delphi FMX releases but was fixed by EMBA later. There also were disputes in FPC forums/wiki about CodeTyphon pirating some open-source components. See answer by Peter Dunne below.
Your question is akin to asking the difference between Linux and Ubuntu. Lazarus is an IDE/component library, based on FreePascal (FPC). And CodeTyphon is a distribution of Lazarus and FPC. So CodeTyphon is just one way to install a functioning installation of Lazarus.
Lazarus uses the same floating window design as older versions of Delphi. Installing from CodeTyphon won't change that.
Myself and several friends highlighted several licensing issues with codetyphon
most of which could have been corrected by sourcing the included files from known good source and ensuring the correct license headers were included
PirateLogic refused to correct the issues which means they are using code in direct violation of the original license terms
The fact its open source code does not change the fact they are pirating the code by not including the correct license even after the issue was highlighted
I also found several instances of copyright code included which appears to be proprietary and not FOSS at all
They also changed the path & file names on some libraries so that source is no longer compatible with standard lazarus/component installs
This in my view is totally illogical
These 2 factors heavily undermine what was potentially the best FPC/Lazarus distro
Hardly professional
Lazarus can be a daunting installation process due to it's nature as a cross compiling environment. You don't just download an installer and click ok. A typical "installation" is actually a bootstrap FPC compiler doing a three-pass compilation of an "install". There are plenty of good installation scripts/methods from the official Lazarus/FPC team and in the community for a . But, understandably, the installation process is a skill in itself.
CodeTyphon is a a different/separate branch of an installer system, which is more of a utility suite/tools/third party code compilation library. If you want the simplest installation experience go with CodeTyphon. It has the nice graphical front end for managing the compiler. You can conveniently do the fancy stuff like build "cross-compilers" for almost every "target" operating system out there. It also is jam packed with hundreds of the best components/libraries pre-installed. It is a very actively maintained project and very professional. A whole lot of work is done for you.
Even if you want to be learn the low level compiler capabilities, CodeTyphon is a good place to start. It is written in FCP/Lazarus and is open source. Simply study it as "working demo app" and the other info on the compiler details. If you crash it, at least you don't have to learn to climb the hill. You get to get to start from the top and lose control on the way down. Start from scratch (and a three hour reinstallation) Hahaha
Lazarus also has a package "AnchorDock" which allows you to dock all the windows into one. Either install the anchor dock design package after installing Lazarus, or install Lazarus using the script at getlazarus.org which will do it for you.

Mono on embedded ARM experience?

I'm evaluating components for a new embedded platform. CPU is an ARM9 and OS is Linux. Because the platform will be in use at least for 10 years I think the language should be chosen carefully as well. I'm already running Mono on possible target platform. Beside that I'm to dumb to compile Mono with my Compiler (according to Google more or less everyone else has the same problems), it's already running. I've written some benchmarks for our specific needs and I was quite impressed that Mono was never more than twice as slow compared to plain C. Memory usage is OK, and when I remove all unneeded files the footprint is acceptable. I just like to know if anyone else uses Mono on an embedded platform? Did you have any problems? Things which everyone should consider?
Given that the iPhone and Android are ARM, Mono is very well supported on ARM. And because Novell sells supported versions of Mono targeting those platforms, it is likely to stay well supported for quite some time.
One thing to note is the Mono runtime is licensed under the LGPL, so you need to ensure your usage complies with the license, or you will need to purchase a commercial license for Mono.

Is it possible to run a compiled program with Xcode on Mac OS X in FreeBSD? (Objective-C/Cocoa)

I have a plan to build a web-site which running CGI made with Cocoa.
My final goal is develop on Mac OS X, and run on FreeBSD.
Is this possible?
As I know, there is a free implementation of some NextStep classes, the GNUStep.
The web-site is almost built with only strings. I read GNUStep documents, classes are enough. DB connection will be made with C interfaces.
Most biggest problem which I'm concerning is linking and binary compatibility. I'm currently configuring FreeBSD on VirtualBox, but I wanna know any possibility informations about this from experts.
This is not a production server. Just a trial. Please feel free to saying anything.
--edit--
I confused Foundation and Cocoa frameworks. What I said was Foundation. Basic classes which just enough to manipulating strings.
It’s entirely possible to cross-develop using Xcode. The Cocotron does this – and provides an implementation of Foundation – but doesn’t currently target FreeBSD. You could probably use it as a template to set up cross-development for BSD targets using GNUstep, but it won’t be easy.
You should be OK with the GNUstep Foundation on FreeBSD 9.0 with Objective-C 2 (clang). See these instructions.
Note: Do not installing under '/' with a FreeBSD default install, because it has little space on the '/' partition. I've used /usr/local/gnustep instead, and made some links as the instructions suggest.
Note II: GNUstep sources from subversion repository didn't compile for me, so I used the latest stable GNUstep sources.
Yes, you can do this, and I am doing it right now successfully using FreeBSD 8.2 and Xcode 4.0, running the Foundation class from The Cocotron. Here is a link: describing exactly what I did to build the cross compiler and set everything up. I also detail in that post, how I attempted to get AppKit (GUI) to work. I failed, it may work in the future, it doesn't fully work yet.
So far it's great. I use a common codebase to write iPhone App (game client) and FreeBSD Game Server; after my server compiles I even have a target rsync the files to my dev box.
One more note, you mention DB, I'm successfully using mysqlclient libraries within my App and my post details how to do that. Since you're building a cross-compiler with The Cocotron you can use any library. Just install the library on FreeBSD first, then create the platform as described.
Sounds like your trying to shoehorn tools onto OS and hardware they were not designed for. There are hacks to get almost anything running on top of anything else but why ask for all the grief?
The entire point of the entire Apple API is that you have integration from hardware to OS to development tools. You supposed to pay more up front in return for greater robustness and lower over all lifecycle cost. (It doesn't always work just like Linux doesn't always save money and Windows doesn't always provide the software choices you need but that is the design goal.) When you break Apple's hardware-OS-Dev trinity you have to start fighting the API and the hardware instead of letting it work for you.
I don't think what you're doing will work and even if it does it will cost a lot of time and in the end time is money. Unless your being forced by external circumstances beyond your control to use this configuration, I would strongly suggest you do whatever it takes to find another way to accomplish what you want.
You won't get binary compatibility. Mac OS X uses the Mach-O object format and FreeBSD uses ELF, like linux. Cocoa won't work on platforms other than Mac OS, but if you stick to POSIX and open-source libraries though, you shouldn't have too much trouble building your CGI (and any dependencies) on your FreeBSD machine.
Also, Cocoa for a website? It's the Mac OS standard library for GUIs, associated datastructures, and various helpers. Apple used to promote something called WebObjects which was similar to Cocoa for the web, but I haven't heard anything about it in ages. I don't think Cocoa will work for a website, unless you just mean write a custom web server that has a graphical front-end in Cocoa.

Differences between CruiseControl (original) and CruiseControl.NET

Are there any differences between the original CruiseControl and the .NET port? I've compared the 2, but can't find any big differences except the language it has been developed in. I want to use either one of them for (automated) testing of web applications, using Selenium and Subversion, perhaps even Groovy but don't know which to choose.
[edit]
After looking at CC and Hudson, I've chosen Hudson for it's simplicity, it already has plugins to run Groovy scripts and Selenium as well
Choose me, choose me! (I work on the original CruiseControl.)
I've never used CC.NET but from what I know I agree that they are pretty comparable. Probably the most important difference is cross-platform vs. Windows only.
Now I wonder how long until someone comes by and says their both crap and you should try Hudson? ;)
(And of course there are lots of other choices...)
CruiseControl.NET (cc.net henceforth) has build queues (http://confluence.public.thoughtworks.org/display/CCNET/Project+Configuration+Block), which allows you to serialize builds that depends on a certain build order. I'm in the process of emulating this behavior in the java version of cruisecontrol but the functionality doesn't map one to one. The reason however, that I'm at all moving from the .net to the java version is that the .net version core dumps with mono (cc.net nightly build and mono nightly build as of two months ago). The fault lies with monos thread handling but voids attempts to get cc.net up and running.
The documentation on this can be tricky to find, if you don't notice the version numbers that the configuration examples/documentation adhere to (confluence.public.thoughtworks.org has the updated configuration documentation whereas ccnet.sourceforge.net has not. I know that the ccnet is most likely a dead site, but if your're not carefully reading the datestamps on every page you're visiting, this may bite you).
Furthermore, the sourcecontrol blocks for cvs and svn in cc.net are more granular and featurerich than their counterpart in the java version, but this has not been a problem in my work. The java version is also easy to extend/modify re: plugin behavior, but you would really just like to see this kind of work going upstream instead of forking.
I'm fairly impressed with both the java version and the fork in .net (modulo mono runtime behavior), but you really do not want to try any of the other forks of cruisecontrol. I've had peripheral experience with hudson, and the features were just not compelling enough to veer me from cruisecontrol. Hudson has a (somewhat coloured) comparison map of Hudson and CruiseControl (java) at http://hudson.gotdns.com/wiki/display/HUDSON/Home
A viable alternative is the python implemented buildbot (http://buildbot.net/trac). It does not have fancy gui dashboards and the setup is somewhat more commandline-bound, but if you're doing distributed builds, it's very easy to set up and get running.
I think for you it will come down to operating system, original can run on nix, and .net version runs on windows.
There are other automated build utilities that can do this as well, such as TeamCity in the windows space, and cruisecontrol.rb in the ruby world.
Also there is a PowerShell based build utility called pSake that can poll subversion and perform tasks.