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  • MSCC: Scripting - Administrator's­ toolbox of magic...

    Finally, we made it to have our April meetup - in May. The most obvious explanation is the increased amount of open source and IT activities that either the MSCC, the Linux User Group of Mauritius (LUGM), or the University of Mauritius Student's Computer Club is organising. It's absolutely incredible to see the recent hype of events here on the island. And I'm loving it! Unfortunately, we also had to deal with arranging for a location this time. It was kind of an odyssey as my requests (and phone calls) haven't been answered, even though I tried it several times - well, kind of disappointing and I have to look into that for future gatherings. In my opinion, it is essential that two parameters of a community meeting are fixed as early as possible: Location, and Date and time You can't just change one or both on the very last minute. Well, this time we had to do it due to unforeseen reasons, and I apologise to any MSCC member which couldn't make it to our April meetup. Okay, lesson learned but now back to the actual meetup report ... Shortly after the meeting I placed the following statement as my first impression: "Spontaneous and improvised :) No, seriously, Ish and Dan had well prepared presentations on shell scripting, mainly focused towards Bourne Again Shell (bash), and the pros and cons of scripting versus actually writing something in a decent programming language. I thought that I could cut myself out of the equation but the demand for information about PowerShell was higher than expected..." Well, it turned out that the interest in Windows PowerShell was high, as I even got a couple of questions on it via social media networks during the evening. I also like to mention that the number of attendees went back to what I would call a "standard" number of participation. This time there were 12 craftsmen, but again a good number of First Timers. Reactions of other attendees Here are some impressions and feedback from our participants: "Enjoyed the bash and powershell (linux / windows) presentations ..." -- Nadim on event comments "He [Daniel] also showed us some syntax loopholes in Bash that could leave someone with bad code." -- Ish on MSCC – Let's talk about Scripting   Glad to see a couple of first time attendees, especially students from the university itself. Some details on the presentations MSCC: First time visit at the University of Mauritius - Phase II Engineering Tower, room 2.9 Gimme some love ... bash and other shells Ish gave a great introduction into shell scripting as he spoke about existing shell environments and a little bit about their history. Furthermore, he talked about various built-in commands, the use of coreutils, the ability to daisy-chain multiple commands using pipes, the importance of the standard I/O streams and their file descriptors in advanced scripting techniques. Combined with a couple of sample statements in the Linux terminal on Ubuntu 14.04 machine it was a solid presentation. Have a closer look at his slides - published on his blog on MSCC – Let's talk about Scripting. Oddities of scripting After the brief introduction into bash it was Daniel's turn to highlight a good number of oddities when working with shell scripts. First of all, it should be clear that scripting is not supposed for any kind of implementations in terms of software but simply to automate administrative procedures and to simplify routine jobs on a system. One of the cool oddities that he mentioned is that everything (!) in a shell is represented by strings; there are no other types like integer, float, date-time, etc. that you'd like to use in a full-fledged programming language. Let's have a look at his sample:  more to come... What's the output? As a conclusion, Daniel suggests that shell scripting should be limited but not restricted to automatic repetitive command stacks and batch jobs, startup wrapper for applications in order to set up the execution environment, and other not too sophisticated jobs. But as soon as it might involve a little bit more logic or you might rely on performance it's better to write an application in Ruby, Python, or Perl (among others of course). This is also enables the possibility to test your code properly. MSCC: Ish talking about Bourne Again Shell (bash) and shell scripting to automate regular tasks MSCC: Daniel gives an overview about the pros and cons of shell scripting versus programming MSCC: PowerShell as your scripting solution on Windows operating systems The path of the Enlightened is long ... and tough. Honestly, even though PowerShell was mentioned without any further details on the meetup's agenda, I didn't expect that there would be demand to give a presentation on Microsoft PowerShell after all. I already took this topic out of the announcement but the audience wanted to have some information. Okay, then let's see what I could do - improvised style. While my machine booted and got hooked up to the projector, I started to talk about the beginnings of PowerShell from back in 2006, and its predecessors MS DOS and Command Prompt. A throwback in history... always good for young people. As usual, Microsoft didn't get it at that time. Instead of listening to their client's needs and demands they ignored the feasibility to administrate Windows server farms without any UI tools. PowerShell is actually a result of this, and seeing that shell scripting is a common, reliable and fast way in an administrator's toolbox for decades, Microsoft had to adapt from their Microsoft Management Console (MMC) to a broader approach. It's not like shell scripting was something new; it is in daily use by alternative operating systems like AIX, HP UX, Solaris, and last but not least Linux. Most interestingly, Microsoft is very good at renovating existing architectures, and over the years PowerShell not only replaced their own combination of Command Prompt and Scripting Hosts (VBScript and CScript) but really turned into a challenging competitor on the market. The shell is easy to extend with cmdlets, and open to other Microsoft products like SQL Server, SharePoint, as well as Third-party software applications. Similar to MMC PowerShell also offers the ability to administer other machine remotely - only without a graphical user interface and therefore it's easier to automate and schedule regular tasks. Following is a sample of a PowerShell script file (extension .ps1): $strComputer = "." $colItems = get-wmiobject -class Win32_BIOS -namespace root\CIMV2 -comp $strComputer foreach ($objItem in $colItems) {write-host "BIOS Characteristics: " $objItem.BiosCharacteristicswrite-host "BIOS Version: " $objItem.BIOSVersionwrite-host "Build Number: " $objItem.BuildNumberwrite-host "Caption: " $objItem.Captionwrite-host "Code Set: " $objItem.CodeSetwrite-host "Current Language: " $objItem.CurrentLanguagewrite-host "Description: " $objItem.Descriptionwrite-host "Identification Code: " $objItem.IdentificationCodewrite-host "Installable Languages: " $objItem.InstallableLanguageswrite-host "Installation Date: " $objItem.InstallDatewrite-host "Language Edition: " $objItem.LanguageEditionwrite-host "List Of Languages: " $objItem.ListOfLanguageswrite-host "Manufacturer: " $objItem.Manufacturerwrite-host "Name: " $objItem.Namewrite-host "Other Target Operating System: " $objItem.OtherTargetOSwrite-host "Primary BIOS: " $objItem.PrimaryBIOSwrite-host "Release Date: " $objItem.ReleaseDatewrite-host "Serial Number: " $objItem.SerialNumberwrite-host "SMBIOS BIOS Version: " $objItem.SMBIOSBIOSVersionwrite-host "SMBIOS Major Version: " $objItem.SMBIOSMajorVersionwrite-host "SMBIOS Minor Version: " $objItem.SMBIOSMinorVersionwrite-host "SMBIOS Present: " $objItem.SMBIOSPresentwrite-host "Software Element ID: " $objItem.SoftwareElementIDwrite-host "Software Element State: " $objItem.SoftwareElementStatewrite-host "Status: " $objItem.Statuswrite-host "Target Operating System: " $objItem.TargetOperatingSystemwrite-host "Version: " $objItem.Versionwrite-host} Which gives you information about your BIOS and Windows OS. Then change the computer name to another one on your network (NetBIOS based) and run the script again. There lots of samples and tutorials at the Microsoft Script Center, and I would advise you to pay a visit over there if you are more interested in PowerShell. The Script Center provides the download links, too. Upcoming Events What are the upcoming events here in Mauritius? So far, we have the following ones (incomplete list as usual) in chronological order: Hacking Defence (14. May 2014) WebCup Maurice (7. & 8. June 2014) Developers Conference (TBA ~ July 2014) Linuxfest 2014 (TBA ~ November 2014) Hopefully, there will be more announcements during the next couple of weeks and months. If you know about any other event, like a bootcamp, a code challenge or hackathon here in Mauritius, please drop me a note in the comment section below this article. Thanks! My resume of the day Spontaneous and improvised :) The new location at the University of Mauritius turned out very well, there is plenty of space, and it could be a good choice for future meetings. Especially, having the ability to get more and more students into our IT community sounds like a great opportunity. Later during the day, I got some promising mails from Nadim regarding future sessions at the local branch of the Middlesex University. Well, we will see in the future... But for now this will be on hold until approximately October when students resume their regular studies. Anyway, it was a good experience at the university, and thanks again to the UoM Student's Computer Club that made the necessary arrangements for the MSCC!

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  • Xcode newb -- #include can't find my file

    - by morgancodes
    I'm trying to get a third party audio library (STK) working inside Xcode. Along with the standard .h files, many of the implementation files include a file called SKINI.msg. SKINI.msg is in the same directory as all of the header files. The header files are getting included fine, but the compiler complains that it can't find SKINI.msg. What do I need to do to get Xcode to happily include SKINI.msg? Edit: Here's the contents of SKINI.msg: /*********************************************************/ /* Definition of SKINI Message Types and Special Symbols Synthesis toolKit Instrument Network Interface These symbols should have the form: \c __SK_<name>_ where <name> is the string used in the SKINI stream. by Perry R. Cook, 1995 - 2010. */ /*********************************************************/ namespace stk { #define NOPE -32767 #define YEP 1 #define SK_DBL -32766 #define SK_INT -32765 #define SK_STR -32764 #define __SK_Exit_ 999 /***** MIDI COMPATIBLE MESSAGES *****/ /*** (Status bytes for channel=0) ***/ #define __SK_NoteOff_ 128 #define __SK_NoteOn_ 144 #define __SK_PolyPressure_ 160 #define __SK_ControlChange_ 176 #define __SK_ProgramChange_ 192 #define __SK_AfterTouch_ 208 #define __SK_ChannelPressure_ __SK_AfterTouch_ #define __SK_PitchWheel_ 224 #define __SK_PitchBend_ __SK_PitchWheel_ #define __SK_PitchChange_ 49 #define __SK_Clock_ 248 #define __SK_SongStart_ 250 #define __SK_Continue_ 251 #define __SK_SongStop_ 252 #define __SK_ActiveSensing_ 254 #define __SK_SystemReset_ 255 #define __SK_Volume_ 7 #define __SK_ModWheel_ 1 #define __SK_Modulation_ __SK_ModWheel_ #define __SK_Breath_ 2 #define __SK_FootControl_ 4 #define __SK_Portamento_ 65 #define __SK_Balance_ 8 #define __SK_Pan_ 10 #define __SK_Sustain_ 64 #define __SK_Damper_ __SK_Sustain_ #define __SK_Expression_ 11 #define __SK_AfterTouch_Cont_ 128 #define __SK_ModFrequency_ __SK_Expression_ #define __SK_ProphesyRibbon_ 16 #define __SK_ProphesyWheelUp_ 2 #define __SK_ProphesyWheelDown_ 3 #define __SK_ProphesyPedal_ 18 #define __SK_ProphesyKnob1_ 21 #define __SK_ProphesyKnob2_ 22 /*** Instrument Family Specific ***/ #define __SK_NoiseLevel_ __SK_FootControl_ #define __SK_PickPosition_ __SK_FootControl_ #define __SK_StringDamping_ __SK_Expression_ #define __SK_StringDetune_ __SK_ModWheel_ #define __SK_BodySize_ __SK_Breath_ #define __SK_BowPressure_ __SK_Breath_ #define __SK_BowPosition_ __SK_PickPosition_ #define __SK_BowBeta_ __SK_BowPosition_ #define __SK_ReedStiffness_ __SK_Breath_ #define __SK_ReedRestPos_ __SK_FootControl_ #define __SK_FluteEmbouchure_ __SK_Breath_ #define __SK_JetDelay_ __SK_FluteEmbouchure_ #define __SK_LipTension_ __SK_Breath_ #define __SK_SlideLength_ __SK_FootControl_ #define __SK_StrikePosition_ __SK_PickPosition_ #define __SK_StickHardness_ __SK_Breath_ #define __SK_TrillDepth_ 1051 #define __SK_TrillSpeed_ 1052 #define __SK_StrumSpeed_ __SK_TrillSpeed_ #define __SK_RollSpeed_ __SK_TrillSpeed_ #define __SK_FilterQ_ __SK_Breath_ #define __SK_FilterFreq_ 1062 #define __SK_FilterSweepRate_ __SK_FootControl_ #define __SK_ShakerInst_ 1071 #define __SK_ShakerEnergy_ __SK_Breath_ #define __SK_ShakerDamping_ __SK_ModFrequency_ #define __SK_ShakerNumObjects_ __SK_FootControl_ #define __SK_Strumming_ 1090 #define __SK_NotStrumming_ 1091 #define __SK_Trilling_ 1092 #define __SK_NotTrilling_ 1093 #define __SK_Rolling_ __SK_Strumming_ #define __SK_NotRolling_ __SK_NotStrumming_ #define __SK_PlayerSkill_ 2001 #define __SK_Chord_ 2002 #define __SK_ChordOff_ 2003 #define __SK_SINGER_FilePath_ 3000 #define __SK_SINGER_Frequency_ 3001 #define __SK_SINGER_NoteName_ 3002 #define __SK_SINGER_Shape_ 3003 #define __SK_SINGER_Glot_ 3004 #define __SK_SINGER_VoicedUnVoiced_ 3005 #define __SK_SINGER_Synthesize_ 3006 #define __SK_SINGER_Silence_ 3007 #define __SK_SINGER_VibratoAmt_ __SK_ModWheel_ #define __SK_SINGER_RndVibAmt_ 3008 #define __SK_SINGER_VibFreq_ __SK_Expression_ } // stk namespace And here's what the compiler said: CompileC build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/Objects-normal/i386/BandedWG.o "../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp" normal i386 c++ com.apple.compilers.gcc.4_2 cd /Users/morganpackard/Desktop/trashme/StkCompile setenv LANG en_US.US-ASCII setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 -x c++ -arch i386 -fmessage-length=0 -pipe -Wno-trigraphs -fpascal-strings -fasm-blocks -O0 -Wreturn-type -Wunused-variable -D__IPHONE_OS_VERSION_MIN_REQUIRED=30000 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.2.sdk -fvisibility=hidden -fvisibility-inlines-hidden -mmacosx-version-min=10.5 -gdwarf-2 -iquote /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-generated-files.hmap -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-own-target-headers.hmap -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-all-target-headers.hmap -iquote /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/StkCompile-project-headers.hmap -F/Users/morganpackard/Desktop/trashme/StkCompile/build/Debug-iphonesimulator -I/Users/morganpackard/Desktop/trashme/StkCompile/build/Debug-iphonesimulator/include -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/DerivedSources/i386 -I/Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/DerivedSources -include /var/folders/dx/dxSUSyOJFv0MBEh9qC1oJ++++TI/-Caches-/com.apple.Xcode.501/SharedPrecompiledHeaders/StkCompile_Prefix-bopqzvwpuyqltrdumgtjtfrjvtzb/StkCompile_Prefix.pch -c "/Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp" -o /Users/morganpackard/Desktop/trashme/StkCompile/build/StkCompile.build/Debug-iphonesimulator/StkCompile.build/Objects-normal/i386/BandedWG.o /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:33:21: error: SKINI.msg: No such file or directory /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp: In member function 'virtual void stk::BandedWG::controlChange(int, stk::StkFloat)': /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:326: error: '__SK_BowPressure_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:342: error: '__SK_AfterTouch_Cont_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:349: error: '__SK_ModWheel_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:357: error: '__SK_ModFrequency_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:359: error: '__SK_Sustain_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:363: error: '__SK_Portamento_' was not declared in this scope /Users/morganpackard/Desktop/trashme/StkCompile/../../../Data/study/iPhone class/stk-4.4.2/src/BandedWG.cpp:367: error: '__SK_ProphesyRibbon_' was not declared in this scope

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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  • The Java Specialist: An Interview with Java Champion Heinz Kabutz

    - by Janice J. Heiss
    Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

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  • MSCC: Global Windows Azure Bootcamp

    Mauritius participated and contributed to the Global Windows Azure Bootcamp 2014 (GWAB). Again! And this time stronger than ever, and together with 137 other locations in 56 countries world-wide. We had 62 named registrations, 7 guest additions and approximately 10 offline participants prior to the event day. Most interestingly the organisation of the GWAB through the MSCC helped to increased the number of craftsmen. The Mauritius Software Craftsmanship Community has currently 138 registered members - in less than one year! Only with those numbers we can proudly say that all the preparations and hard work towards this event already paid off. Personally, I'm really grateful that we had this kind of response and the feedback from some attendees confirmed that the MSCC is on the right track here on Cyber Island Mauritius. Inspired and motivated by the success of this event, rest assured that there will be more public events like the GWAB. This time it took some time to reflect on our meetup, following my first impression right on spot: "Wow, what an experience to organise and participate in this global event. Overall, I've been very pleased with the preparations and the event itself. Surely, there have been some nicks that we have to address and to improve for future activities like this. Quite frankly, we are not professional event organisers (not yet) but we learned a lot over the past couple of days. A big Thank You to our event sponsors, namely Microsoft Indian Ocean Islands & French Pacific, Ceridian Mauritius and Emtel. Without them this event wouldn't have happened - Thank You! And to the cool team members of Microsoft Student Partners (MSPs). You geeks did a great job! Thanks!" So, how many attendees did we actually have? 61! - Awesome - 61 cloud computing instances to help on the research of diabetes. During Saturday afternoon there was even an online publication on L'Express: Les développeurs mauriciens se joignent au combat contre le diabète Reactions of other attendees Don't take my word for granted... Here are some impressions and feedback from our participants: "Awesome event, really appreciated the presentations :-)" -- Kevin on event comments "very interesting and enriching." -- Diana on event comments "#gwab #gwabmru 2014 great success. Looking forward for gwab 2015" -- Wasiim on Twitter "Was there till the end. Awesome Event. I'll surely join upcoming meetup sessions :)" -- Luchmun on event comments "#gwabmru was not that cool. left early" -- Mohammad on Twitter The overall feedback is positive but we are absolutely aware that there quite a number of problems we had to face. We are already looking into that and ideas / action plans on how we will be able to improve it for future events. The sessions We started the day with welcoming speeches by Thierry Coret, Sr. Marketing Manager of Microsoft Indian Ocean Islands & French Pacific and Vidia Mooneegan, Managing Director and Sr. Vice President of Ceridian Mauritius. The clear emphasis was on the endless possibilities of cloud computing and how it can enable any kind of sectors here in the country. Then it was about time to set up the cloud computing services in order to contribute each attendees cloud computing resources to the global research of diabetes, a step by step guide presented by Arnaud Meslier, Technical Evangelist at Microsoft. Given a rendering package and a configuration file it was very interesting to follow the single steps in Windows Azure. Also, during the day we were not sure whether the set up had been correctly, as Mauritius didn't show up on the results board - which should have been the case after approximately 20 to 30 minutes. Anyways, let the minions work... Next, Arnaud gave a brief overview of the variety of services Windows Azure has to offer. Whether you need a development environment for your websites or mobiles app, running a virtual machine with your existing applications or simply putting a SQL database online. No worries, Windows Azure has the right packages available and the online management portal is really easy t handle. After this, we got a little bit more business oriented while Wasiim Hosenbocus, employee at Ceridian, took the attendees through the inerts of a real-life application, and demoed a couple of the existing features. He did a great job by showing how the different services of Windows Azure can be created and pulled together. After the lunch break it is always tough to keep the audience awake... And it was my turn. I gave a brief overview on operating and managing a SQL database on Windows Azure. Well, there are actually two options available and depending on your individual requirements you should be aware of both. The simpler version is called SQL Database and while provisioning only takes a couple of seconds, you should take into consideration that SQL Database has a number of constraints, like limitations on the actual database size - up to 5 GB as web edition and up to 150 GB maximum as business edition -, among others. Next, it was Chervine Bhiwoo's session on Windows Azure Mobile Services. It was absolutely amazing to see that the mobiles services directly offers you various project templates, like Windows 8 Store App, Android app, iOS app, and even Xamarin cross-platform app development. So, within a couple of minutes you can have your first mobile app active and running on Windows Azure. Furthermore, Chervine showed the attendees that adding another user interface, like Web Sites running on ASP.NET MVC 4 only takes a couple of minutes, too. And last but not least, we rounded up the day with Windows Azure Websites and hosting of Virtual Machines presented by some members of the local Microsoft Students Partners programme. Surely, one of the big advantages using Windows Azure is the availability of pre-defined installation packages of known web applications, like WordPress, Joomla!, or Ghost. Compared to running your own web site with a traditional web hoster it is surely en par, and depending on your personal level of expertise, Windows Azure provides you more liberty in terms of configuration than maybe a shared hosting environment. Running a pre-defined web application is one thing but in case that you would like to have more control over your hosting environment it is highly advised to opt for a virtual machine. Provisioning of an Ubuntu 12.04 LTS system was very simple to do but it takes some more minutes than you might expect. So, please be patient and take your time while Windows Azure gets everything in place for you. Afterwards, you can use a SecureShell (ssh) client like Putty in case of a Linux-based machine, or Remote Desktop Services when operating a Windows Server system to log in into your virtual machine. At the end of the day we had a great Q&A session and we finalised the event with our raffle of goodies. Participation in the raffle was bound to submission of the session survey and most gratefully we had a give-away for everyone. What a nice coincidence to finish of the day. Note: All session slides (and demo codes) will be made available on the MSCC event page. Please, check the Files section over there. (Some) Visual impressions from the event Just to give you an idea about what has happened during the GWAB 2014 at Ebene... Speakers and Microsoft Student Partners are getting ready for the Global Windows Azure Bootcamp 2014 GWAB 2014 attendees are fully integrated into the hands-on-labs and setting up their individuals cloud computing services 60 attendees at the GWAB 2014. Despite some technical difficulties we had a great time running the event GWAB 2014: Using the lunch break for networking and exchange of ideas - Great conversations and topics amongst attendees There are more pictures on the original event page: Questions & Answers Following are a couple of questions which have been asked and didn't get an answer during the event: Q: Is it possible to upload static pages via FTP? A: Yes, you can. Have a look at the right side column on the dashboard of your website. There you'll find information about the FTP and SFTP host names. You can use any FTP client, like ie. FileZilla to log in. FTP also gives you access to your log files. Q: What are the size limitations on SQL Database? A: 5 GB on the Web Edition, and 150 GB on the business edition. A maximum 150 databases (inclusing 'master') per SQL Database server. More details here: General Guidelines and Limitations (Azure SQL Database) Q: What's the maximum size of a SQL Server running in a Virtual Machine? A: The maximum Windows Azure VM has currently 8 CPU cores, 14 or 56 GB of RAM and 16x 1 TB hard drives. More details here: Virtual Machine and Cloud Service Sizes for Azure Q: How can we register for Windows Azure? A: Mauritius is currently not listed for phone verification. Please get in touch with Arnaud Meslier at Microsoft IOI & FP Q: Can I use my own domain name for Windows Azure websites? A: Yes, you can. But this might require to upscale your account to Standard. In case that I missed a question and answer, please use the comment section at the end of the article. Thanks! Final results Every participant was instructed during the hands-on-lab session on how to set up a cloud computing service in their account. Of course, I won't keep the results from you... Global Azure Lab GWAB 2014: Our cloud computing contribution to the research of diabetes And I would say Mauritius did a good job! Upcoming Events What are the upcoming events here in Mauritius? So far, we have the following ones (incomplete list as usual) in chronological order: Launch of Microsoft SQL Server 2014 (15.4.2014) Corsair Hackers Reboot (19.4.2014) WebCup (TBA ~ June 2014) Developers Conference (TBA ~ July 2014) Linuxfest 2014 (TBA ~ November 2014) Hopefully, there will be more announcements during the next couple of weeks and months. If you know about any other event, like a bootcamp, a code challenge or hackathon here in Mauritius, please drop me a note in the comment section below this article. Thanks! Networking and job/project opportunities Despite having technical presentations on Windows Azure an event like this always offers a great bunch of possibilities and opportunities to get in touch with new people in IT, have an exchange of experience with other like-minded people. As I already wrote about Communities - The importance of exchange and discussion - I had a great conversation with representatives of the University des Mascareignes which are currently embracing cloud infrastructure and cloud computing for their various campuses in the Indian Ocean. As for the MSCC it would be a great experience to stay in touch with them, and to work on upcoming, common activities. Furthermore, I had a very good conversation with Thierry and Ludovic of Microsoft IOI & FP on the necessity of user groups and IT communities here on the island. It's great to see that the MSCC is currently on a run and that local companies are sharing our thoughts on promoting IT careers and exchange of IT knowledge in such an open way. I'm also looking forward to be able to participate and to contribute on more events in the near future. My resume of the day We learned a lot today and there is always room for improvement! It was an awesome event and quite frankly it was a pleasure to spend the day with so many enthuastic IT people in the same room. It was a great experience to organise such event locally and participate on a global scale to support the GlyQ-IQ Technology in their research on diabetes. I was so pleased to see the involvement of new MSCC members in taking the opportunity to share and learn about the power of cloud computing. The Mauritius Software Craftsmanship Community is on the right way and this year's bootcamp on Windows Azure only marked the beginning of our journey. Thank you to our sponsors and my kudos to the MSPs! Update: Media coverage The event has been reported in local media, too. Following are some resources: Orange - Local - Business: Le cloud, pour des recherches approfondies sur le diabète Maurice Info.mu: Le cloud, pour des recherches approfondies sur le diabète Le Quotidien Pg 2: Global Windows Azure Bootcamp 2014 - Le cloud pour des recherches approfondies sur le diabète The Observer Pg 12: Le cloud, pour des recherches approfondies sur le diabète

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