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  • Annotate source code with diagrams as comments

    - by Steven Lu
    I write a lot of (primarily c++ and javascript) code that touches upon computational geometry and graphics and those kinds of topics, so I have found that visual diagrams have been an indispensable part of the process of solving problems. I have determined just now that "oh, wouldn't it just be fantastic if I could somehow attach a hand-drawn diagram to a piece of code as a comment", and this would allow me to come back to something I worked on, days, weeks, months earlier and far more quickly re-grok my algorithms. As a visual learner, I feel like this has the potential to improve my productivity with almost every type of programming because simple diagrams can help with understanding and reasoning about any type of non-trivial data structure. Graphs for example. During graph theory class at university I had only ever been able to truly comprehend the graph relationships that I could actually draw diagrammatical representations of. So... No IDE to my knowledge lets you save a picture as a comment to code. My thinking was that I or someone else could come up with some reasonably easy-to-use tool that can convert an image into a base64 binary string which I can then insert into my code. If the conversion/insertion process can be streamlined enough it would allow a far better connection between the diagram and the actual code, so I no longer need to chronographically search through my notebooks. Even more awesome: plugins for the IDEs to automatically parse out and display the image. There is absolutely nothing difficult about this from a theoretical point of view. My guess is that it would take some extra time for me to actually figure out how to extend my favorite IDEs and maintain these plugins, so I'd be totally happy with a sort of code post-processor which would do the same parsing out and rendering of the images and show them side by side with the code, inside of a browser or something. Since I'm a javascript programmer by trade. What do people think? Would anyone pay for this? I would.

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  • How to set Guake as preferred terminal emulator for "Run in Terminal"?

    - by d3vid
    I've recently installed Guake and like it a lot. I'd like to set it as my preferred terminal application. That is, when I right-click on a bash script file, click "Open", and choose "Run in Terminal", I want it to open in a new Guake tab. I'm not sure where to set Guake as the preferred app for "Run in Terminal". And I'm guessing that I might need the command to be something like guake --new-tab=new --execute-command="COMMANDHERE", so how do I pass that parameter? Ideally, I'd like a terminal invocation to open a new Guake tab, unless there is already one available. (Difficult to tell, what id there's already a command running in the existing tab?) Failing that, just opening a new Guake tab is ok. Also, is there an option to keep Guake hidden when this happens? Already tried: Based on How can I set default terminal used? I have already tried: gconftool --type string --set /desktop/gnome/applications/terminal/exec guake - this made Guake appear when I type Ctrl-Alt-T. setting x-terminal-emulator to \usr\bin\guake in Alternatives Configurator - this made no difference (having already made the previous change).

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  • SQL SERVER – Introduction to PERCENT_RANK() – Analytic Functions Introduced in SQL Server 2012

    - by pinaldave
    SQL Server 2012 introduces new analytical functions PERCENT_RANK(). This function returns relative standing of a value within a query result set or partition. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. Now let’s have fun following query: USE AdventureWorks GO SELECT SalesOrderID, OrderQty, RANK() OVER(ORDER BY SalesOrderID) Rnk, PERCENT_RANK() OVER(ORDER BY SalesOrderID) AS PctDist FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO The above query will give us the following result: Now let us understand the resultset. You will notice that I have also included the RANK() function along with this query. The reason to include RANK() function was as this query is infect uses RANK function and find the relative standing of the query. The formula to find PERCENT_RANK() is as following: PERCENT_RANK() = (RANK() – 1) / (Total Rows – 1) If you want to read more about this function read here. Now let us attempt the same example with PARTITION BY clause USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) Rnk, PERCENT_RANK() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) AS PctDist FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY PctDist DESC GO Now you will notice that the same logic is followed in follow result set. I have now quick question to you – how many of you know the logic/formula of PERCENT_RANK() before this blog post? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Should programmers itemize testing for projects? [on hold]

    - by Patton77
    I recently hired a programming team to do a port of my iPad app to the iPhone and Android platforms. Now, in a separate contract, I am asking them to implement a bunch of tips on how to play the app, similar like you would find in Candy Crush or Cut the Rope. They want to charge 12 hours @ $35/hr for the "Testing all of the Tips", telling me that normally it would take them more than 25 hours but that they will 'bear the difference'. I am not familiar with this level of itemization, but maybe it's a new practice? I am used to devs doing their own quality control, and then having a testing/acceptance period. They are using Cocos 2D-X, and they say that the tips going to multiple platforms makes all of the hours jack up. I feel like they might be overcharging, and it's difficult for me to know because it's kind of like with a mechanic. "It took us 5 hours to replace the radiator". How can you dispute that? It seems to me that most of you would charge for the work but NOT for hours that you are 'testing'. Am I missing something? Thanks for any help and advice you can give!

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  • SQL SERVER – 2012 – List All The Column With Specific Data Types in Database

    - by pinaldave
    5 years ago I wrote script SQL SERVER – 2005 – List All The Column With Specific Data Types, when I read it again, it is very much relevant and I liked it. This is one of the script which every developer would like to keep it handy. I have upgraded the script bit more. I have included few additional information which I believe I should have added from the beginning. It is difficult to visualize the final script when we are writing it first time. I use every script which I write on this blog, the matter of the fact, I write only those scripts here which I was using at that time. It is quite possible that as time passes by my needs are changing and I change my script. Here is the updated script of this subject. If there are any user data types, it will list the same as well. SELECT s.name AS 'schema', ts.name AS TableName, c.name AS column_name, c.column_id, SCHEMA_NAME(t.schema_id) AS DatatypeSchema, t.name AS Datatypename ,t.is_user_defined, t.is_assembly_type ,c.is_nullable, c.max_length, c.PRECISION, c.scale FROM sys.columns AS c INNER JOIN sys.types AS t ON c.user_type_id=t.user_type_id INNER JOIN sys.tables ts ON ts.OBJECT_ID = c.OBJECT_ID INNER JOIN sys.schemas s ON s.schema_id = t.schema_id ORDER BY s.name, ts.name, c.column_id I would be very interested to see your script which lists all the columns of the database with data types. If I am missing something in my script, I will modify it based on your comment. This way this page will be a good bookmark for the future for all of us. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology

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  • create a simple game board android

    - by user2819446
    I am a beginner in Android and I want to create a very simple 2D game. I've already programmed a Tic-Tac-Toe game. The drawing of the game board and connecting it with my game and input logic was quite difficult (as it was done separately, canvas drawing, calculating positions, etc). By now I figured out that there must be a simpler way. All I want is a simple grid; something like this: http://www.blelb.com/deutsch/blelbspots/spot29/images/hermannneg.gif. The edges should be visible and black, and each cell editable, containing either an image or nothing, so I can detect if the player is on that cell or not, move it... Think of it as Chess or something similar. Searching the internet during the last days, I am a bit overwhelmed of all the different options. After all, I think Gridview or Gridlayout is what I am searching for, but I'm still stuck. I hope you can help me with some good advice or maybe a link to a nice tutorial. I have checked several already, and none were exactly what I was searching for.

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  • Advantages of Singleton Class over Static Class?

    Point 1)Singleton We can get the object of singleton and then pass to other methods.Static Class We can not pass static class to other methods as we pass objectsPoint 2) Singleton In future, it is easy to change the logic of of creating objects to some pooling mechanism. Static Class Very difficult to implement some pooling logic in case of static class. We would need to make that class as non-static and then make all the methods non-static methods, So entire your code needs to be changed.Point3:) Singleton Can Singletone class be inherited to subclass? Singleton class does not say any restriction of Inheritence. So we should be able to do this as long as subclass is also inheritence.There's nothing fundamentally wrong with subclassing a class that is intended to be a singleton. There are many reasons you might want to do it. and there are many ways to accomplish it. It depends on language you use.Static Class We can not inherit Static class to another Static class in C#. Think about it this way: you access static members via type name, like this: MyStaticType.MyStaticMember(); Were you to inherit from that class, you would have to access it via the new type name: MyNewType.MyStaticMember(); Thus, the new item bears no relationships to the original when used in code. There would be no way to take advantage of any inheritance relationship for things like polymorphism. span.fullpost {display:none;}

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  • Part 3: Customization Strategy or how long does it take

    - by volker.eckardt(at)oracle.com
    The previous part in this blog should have made us aware, that many procedures are required to manage all these steps. To review your status let me ask you a question:What is your Customization Strategy?Your answer might be something like, 'customization strategy, well, we have standards and we let requirement documents approve'.Let me ask you another question:How long does it take to redeploy all your customizations into a fresh installation?In 90% of all installations the answer to this question would be: we can't!Although no one would have to do it (hopefully), just thinking about it and recognizing that we have today too many manual steps involved, different procedures and sometimes (undocumented) manual steps to complete a customization installation. And ... in general too many customizations.Why is working with customizations often so complicated and time consuming?Here are the key reasons as I have identified them in my projects:Customization standards defined, but not maintainedDifferent knowledge on developer side (results getting an individual developer touch)No need to automate deployment (not forced by client)Different documentation styles, not easy to hand over to someone elseDifferent development concepts, difficult for the maintenanceJust the minimum present for testing, often positive testing onlyDeviations from naming conventions accepted, although definedComplicated procedures, therefore sometimes partially ignoredAnd last but not least, hand made version control (still)If you would have to 'redeploy all your customizations' you would have to Follow all your own standards and best practiceTrack deviations and define corrective tasksAutomate as much as possible, minimize manual tasksDo not allow any change coming in without version controlUtilize products to support you in deploymentMinimize hand made scripts and extensive documentationReview regularly used techniques to guarantee that all are in line with the current release and also easy maintainableCreate solution libraries and force the team to contribute and reuseDefine quality activities and execute themDefine a procedure to release customizationsI know, it is easy to write down, but much harder to manage. Will provide some guidelines in my next blog.Volker

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  • Approaches to timed puzzle elements

    - by ndg
    I'm working on a side scrolling game that has a number of timed puzzle elements. As a simple example: I have a number of moving platforms that have been setup to transition in a pattern. Ideally I'd like to ensure that as the player first approaches them, they are in an ideal state -- whereby the player can witness the full transition and more experienced players (i.e: speedrunners) can complete the puzzle immediately without having to wait for the current transition to complete. The issue here, in a nutshell, is that because these platforms begin transitioning at the start of the level, it's impossible to correctly calculate when the player is likely to stumble upon them. I've done a fair bit of Googling but haven't managed to turn up any decent resources with regards to solving a problem like this. The obvious solution is to only begin updating the objects when the player (or more likely: the camera) first encounters them. But this becomes difficult when you consider more complicated situations. It seems like potentially the easiest way of handling this is to have an invisible trigger volume that will tell any puzzle elements located inside of it that the player has 'arrived' upon first colliding with the player. But this would mean I'd have to logically group puzzle elements, which could become fairly messy in a hurry. Take, for instance, a puzzle that appears to the right of the screen. It may take the player a number of seconds to reach it. It would look strange if the elements involved were to remain stationary. But by the time the player arrives, it's likely things will be 'out of sync'. I wanted to post here in the hopes that others know of, or have implemented, a decent solution to this problem?

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  • Should programmers itemize testing in testing? [on hold]

    - by Patton77
    I recently hired a programming team to do a port of my iPad app to the iPhone and Android platforms. Now, in a separate contract, I am asking them to implement a bunch of tips on how to play the app, similar like you would find in Candy Crush or Cut the Rope. They want to charge 12 hours @ $35/hr for the "Testing all of the Tips", telling me that normally it would take them more than 25 hours but that they will 'bear the difference'. I am not familiar with this level of itemization, but maybe it's a new practice? I am used to devs doing their own quality control, and then having a testing/acceptance period. They are using Cocos 2D-X, and they say that the tips going to multiple platforms makes all of the hours jack up. I feel like they might be overcharging, and it's difficult for me to know because it's kind of like with a mechanic. "It took us 5 hours to replace the radiator". How can you dispute that? It seems to me that most of you would charge for the work but NOT for hours that you are 'testing'. Am I missing something? Thanks for any help and advice you can give!

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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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  • How to Boost Your Mouse Pointing Accuracy in Windows

    - by The Geek
    Whether you are doing graphics/web design work or just taking screenshots, it’s often very difficult to move the mouse precisely enough to select pixels the way you’d like. Here’s a couple of ways to make it better. There’s a number of methods you can use, from configuring the default mouse settings, to enabling Mouse Keys to move the mouse pointer with the keyboard, or my favorite: Using the Precision Booster feature in IntelliPoint. Image by Rufus Latest Features How-To Geek ETC How to Use the Avira Rescue CD to Clean Your Infected PC The Complete List of iPad Tips, Tricks, and Tutorials Is Your Desktop Printer More Expensive Than Printing Services? 20 OS X Keyboard Shortcuts You Might Not Know HTG Explains: Which Linux File System Should You Choose? HTG Explains: Why Does Photo Paper Improve Print Quality? Ubuntu Font Family Now Available for Download Oh No! WikiLeaks Published Santa Claus’s Naughty List [Video] Remember the Milk Now Supports HTTPS Encryption for the Entire Session MTCrypt Is an Efficient Front End for Mounting TrueCrypt Volumes 10 Things You Should Do with Your New Android Phone Walking Through the Park on a Snowy Night Wallpaper

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  • Get Social At The Oracle Social Summit, November 14–15, 2012, Wynn Las Vegas

    - by Michael Hylton
    More and more power has shifted to the customer with the advent of social media networks—beyond the direct control of the brand. Customers today have so many resources available to them to share their experiences about brands, both positive and negative—it’s astounding and it can be difficult to sift through. Do you know what your customers are saying about your brand? Join top brand marketers, agency executives, and social development leaders for networking and sharing of best practices with industry peers at the Oracle Social Summit, November 14–15, 2012, at the Wynn in Las Vegas, NV. At the Summit you will learn how: Marketing Leaders are bringing key parts of their enterprise together with Social Relationship Management Social Content & Community Managers implement best practices and share tips-of-the-trade for managing a brand's social presence Social Agency & Marketing Developers stay ahead of new social technologies and development best practices Speakers include David Kirkpatrick, founder and CEO of Techonomy Media and author of The Facebook Effect; Reggie Bradford, Oracle Senior Vice President; Matt Dickman, EVP of Social Business Innovation, Weber Shandwick; Matt Thomson, VP of Business Development & Platform, Klout; Lyndsay Iorio, Social Media & Communications Manager, NBC Sports Group; Teresa Caro, VP Social Marketing, Engauge; and many more.  Click here to learn more and register for this exciting social event!

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  • NCurses, scrolling of multiline items, "current item" pointer and "selected items"

    - by mjf
    I am looking for hints/ideas for the best (most effective) way on how to scroll multi-line items as well as emphasizing of the "current item" and "selected items" such as: 1 FOO ITEM 1 Foo sub-item 2 Foo sub-item 3 Foo sub-item 2 BAR ITEM 1 Bar sub-item 3 BAZ ITEM 1 Baz sub-item 2 Baz sub-item 4 RAB ITEM 5 ZZZ ITEM 1 Zzz sub-item 2 Zzz sub-item 3 Zzz sub-item 4 Zzz sub-item using NCurses (some combination of windows, sub-windows, pads, copywin? Uff! In fact, the lines could exceed the stdscr's width so that possibility to scroll left/right would be also nice - pads?)... The whole items (including the sub-items) are supposed to be emphasized as full-width window/pad areas. The "current item" (including it's set of lines) should be emphasized (i.e. using A_BOLD), selected set of items of choice (including the set of lines for each the selected item) should be emphasized in another way (i.e. using A_REVERSE). What would you choose to cope with it the most effective NCurses way? (The less redrawals/refreshes the better and terminal is supposed to have the ability to change it's size - such as XTerm running under "floating window" management.) Thank you for your ideas (or perhaps some piece of code where something similar is already solved - I was not able to find anything helpful on the Internet. I mean I am not going to copy/paste foreign code but programming NCurses properly is still somehow difficult to me). P.S.: Would you suggest to "smooth-scroll" +1/-1 screen line or rather "jump-scroll" +lines/-lines of the items? (I personally prefer the latter one.) Sincerely, -- mjf

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  • Dealing with selfish team member(s)

    - by thegreendroid
    My team is facing a difficult quandary, a couple of team members are essentially selfish (not to be confused with dominant!) and are cherry-picking stories/tasks that will give them the most recognition within the company (at sprint reviews etc. when all the stakeholders are present). These team members are very good at what they do and are fully aware of what they are doing. When we first started using agile about a year ago, I can say I was quite selfish too (coming from a very individual-focused past). I took ownership of certain stories and didn't involve anyone else in it, which in hindsight wasn't the right thing to do and I learnt from that experience almost immediately. We are a young team of very ambitious twenty somethings so I can understand the selfishness to some extent (after all everyone should be ambitious!). But the level to which this selfishness has reached of late has started to bother me and a few others within my team. The way I see it, agile/scrum is all about the team and not individuals. We should be looking out for each other and helping each other improve. I made this quite clear during our last retrospective, that we should be fair and give everyone a chance. I'll wait and see what comes out of it in the next few sprints. In the meantime, what are some of the troubles that you have faced with selfish members and how did you overcome them?

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  • WCF Versioning, Naming and Endpoint URL

    - by Vinothkumar VJ
    I have a WCF Service and a Main Lib1. Say, I have a Save Profile Service. WCF gets data (with predefined data contract) from client and pass the same to the Main Class Lib1, generate response and send it back to client. WCF Method : SaveProfile(ProfileDTO profile) Current Version 1.0 ProfileDTO have the following UserName Password FirstName DOB (In string yyyy-mm-dd) CreatedDate (In string yyyy-mm-dd) Next Version (V2.0) ProfileDTO have the following UserName Password FirstName DOB (In UnixTimeStamp) CreatedDate (In UnixTimeStamp) Version 3.0 ProfileDTO have the following (With change in UserName and Password length validation) UserName Password FirstName DOB (In UnixTimeStamp) CreatedDate (In UnixTimeStamp) In simple we have DataContract and Workflow change between each version 1. How do I name the methods in WCF Service and Main Class Lib1? 2. Do I have to go with any specific pattern for ease development and maintenance? 3. Do I have to have different endpoints for different version? In the above example I have a method named “SaveProfile”. Do I have to name the methods like “SaveProfile1.0”, “SaveProfile2.0”, etc. If that is the case when there is no change between Version “3.0” and “4.0” then there will difficult in maintenance. I’m looking for a approach that will help in ease maintenance

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  • The Hot-Add Memory Hogs

    - by Andrew Clarke
    One of the more difficult tasks, when virtualizing a server, is to determine the amount of memory that Hypervisor should assign to the virtual machine. This requires accurate monitoring and, because of the consequences of setting the value too low, there is a great temptation to err on the side of over-provisioning. This results in fewer guest VMs and, in fact, with more accurate memory provisioning, many virtual environments could support 30% more VMs. In order to achieve a better consolidation (aka VM density) ratio, Windows Server 2008 R2 SP1 has introduced what Microsoft calls ‘Dynamic Memory’. This means that the start-up RAM VM memory assigned to guest virtual machines can be allowed to vary according to demand, changing dynamically while the VM is running, based on the workload of applications running inside. If demand outstrips supply, then memory can be rationed according to the ‘memory weight’ assigned to the guest VM. By this mechanism, memory becomes a shared resource that can be reallocated automatically as demand patterns vary. Unlike VMWare’s Memory Overcommit technology, the sum of all the memory allocations to each virtual machine will not exceed the total memory of the host computer. This is fine for applications that are self-regulating in their demands for memory, releasing memory back into the 'pool' when not under peak load. Other applications however, such as SQL Server Standard and Enterprise, are by nature, memory hogs under high workload; they can grab hot-add memory whilst running under load and then never release it. This requires more careful setting-up and the SQLOS team have provided some guidelines from for configuring SQL Server in virtual environments. Whereas VMWare’s Memory Overcommit is well-proven in a number of different configurations, Hyper-V’s ‘Dynamic Memory’ is new. So far, the indications are that it will improve the business case for virtualizing and it is probably a far more intuitive technology for the average IT professional to grasp. It is certainly worth testing to see whether it works for you.

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  • Advice: The first-time interviewer's dilemna

    - by shan23
    I've been working in my first job for about 2 years now, and I've been "asked" to interview a potential teammate (whom I might have to mentor as well) on pretty short notice (2 days from now). Initially, I had been given a free rein(or so I thought, and hence agreed), but today, I've been told "not to pose bookish questions" - implying I can only ask basic programming puzzles and stuff similar to the 'fizbuzz' question. I strongly believe that not knowing basic algorithmic notations(the haziest ideas of space/time complexities) or the tiniest idea of regular expressions would make working with the guy very difficult for anyone. I know i'm asking for a lot here, but according to you, what would be a comprehensive way to test out the absolutely basic requirements of a CS guy(he has 2 yrs of exp) without sounding too pedantic/bookish etc ? It seems it would be legit to ask C questions/simple puzzles only....but I really do want to have something a bit different from "finding loops in linked lists" that has kind of become the opening statement of most techie interviews !! This is a face-to-face interview with about an hour or more of time - I looked at Steve's basic phone-screen questions, and I was wondering if there exists a guide on "basic face-to-face interview questions" that I can use(or compile from the community's answers here). EDIT: The position is mostly for a kernel level C programming job, with some smattering of C++ required for writing the test framework.

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  • What design patterns are the worst or most narrowly defined?

    - by Akku
    For every programming project, Managers with past programming experience try to shine when they recommend some design patterns for your project. I like design patterns when they make sense or if you need a scalbale solution. I've used Proxies, Observers and Command patterns in a positive way for example, and do so every day. But I'm really hesitant to use say a Factory pattern if there's only one way to create an object, as a factory might make it all easier in the future, but complicates the code and is pure overhead. So, my question is in respect to my future career and my answer to manager types throwing random pattern-names around: Which design patterns did you use, that threw you back overall? Which are the worst design patterns, that you shouldn't have a look at if it's not that only single situation where it makes sense (read: which design patterns are very narrowly defined)? (It's like I was looking for the negative reviews of an overall good product of amazon to see what bugged people most in using design patterns). And I'm not talking about Anti-Patterns here, but about Patterns that are usually thought of as "good" patterns. Edit: As some answered, the problem is most often that patterns are not "bad" but "used wrong". If you know patterns, that are often misused or even difficult to use, they would also fit as an answer.

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  • Run a startup script with lightdm

    - by cheshirekow
    I have a tablet PC and the graphics driver doesn't support xrandr, so in order to rotate the screen I run a script which changes the Xorg.conf file and then restarts lightdm. I also have a script which uses xsetwacom and xinput to change the rotation of the input devices so that the match the new orientation. I've learned how to get the script to run when I login, but I'd like it to run before I login, so that I don't have to enable auto-login with lightdm. I do need it to run though, or the input (touch and pen) is rotated with respect to the screen, so that when I touch the screen the input is in a completely different area, making it really difficult to use the onscreen keyboard. I've looked at other questions on this site. I've tried putting my script in /etc/Xsession.d but that didn't seem to work. I also tried putting it in /etc/rc.local but I think that is the wrong place, nothing seems to happen. I've also tried googling for lightm script hooks, and various other google terms. Any suggestions? Edit 1: After doing some research, it seems to me that it might not be that I want to run a script with lightdm, but rather with the lighdm greeter (in this case, I think the unity-greeter?). Are there any script-hooks for the unity-greeter?

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  • The road to become a programmer [closed]

    - by user68991
    I'm looking for a 'career' change, I don't actually have a career at the moment since I haven't been able to find a job since I graduated with a degree in Materials Engineering. One of my loves has always been computers and programming, though I have never studied it seriously. When I was 11 I wrote a very basic graphical 'game' using notepad and HTML, where I drew each possible position of the main character on the different 'maze' level in MSPaint, using pictures of arrows as links to a new page with the character in a new position, and various other buttons would pop up 'search box', 'press button' etc. At the time I thought this was an amazing achievement of my programming skills. I've used a little bit of FORTRAN 90 whilst I was at university, which rekindled my interest in programming. When I was a kid I mainly used C and HTML, but only very basically as my 'game' suggests. I want to learn a new programming language, I'm not entirely sure where I want to go with it, but the number one contender at the moment is android apps. I'm looking at learning Java, but I've read that it's a difficult place to begin with; so I've also looked at learning Visual Basic, which I believe is also object oriented(?) but a little easier to understand? (not that I know what an object is anyway). Any information people could give me regarding which language to learn, and if there are any good online tutorial for that language I'd really appreciate it. Some of the tutorials I've used so far are full or jargon I can't understand. Also, I'm not afraid of maths having got an engineering degree. Thanks in advance for any help/advice. James

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  • Newbie seeking advice on programming in general

    - by user974685
    need some of you to remember back to a time when you might have been bad at programming... Been at my new job (as a software developer) for a couple of months now, passed probation period. Have very little programming experience (C++ only) and am currently working with asp.net MVC and silverlight. So there's a website the company has been working on and I am joining the effort to make it better, iron out bugs etc. The problem is - learning about a system/website which has already been made, via visual studio. I ALWAYS feel HUGELY overwhelmed, never knowing which part of this line should I look up, and generally having lots of trouble getting the big picture. Visual studio itself is something I'm finding it difficult to get to grips with, let alone the asp.net framework. I get the impression that because my coworkers have more experience than me, they are getting all the good jobs, and I am left with crap to do - stuff which is not even vaguely programming. Meaning they are learning/creating more, and I am learning/creating near nothing. I'm getting demoralised, and too scared to say anything. I'm not stupid, I've read and practiced plenty of the fundamental programming concepts...I'm just bloody scared of this damn framework. I look at it and just feel paralyzed. The result is that I keep asking the older veteran guy of questions, and he is getting irritated, and would rather give me easy/mindless/non programming jobs to avoid wasting time with helping me out. Then when I don't understand something, I'm hesitating about whether or not I should ask him yet, and trying to decide if it would be a waste of time. I'm the kind of person who picks things up slowly, but with a lot of attention to detail. The former I think is making me look incompetent though. Anyone get where I'm coming from please say something helpful....I'm scared of losing my job in a few months or something...

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  • Spring Roo Database Reverse Engineer with Oracle

    - by kerry
    So you are trying to reverse engineer an Oracle database with roo? Unfortunately, due to licensing restrictions with the Oracle JDBC Drivers, this is a little difficult. There are a few blog posts and forum threads that address the problem but I figured I would post what worked for me here. First, you need to download the appropriate Oracle Drivers from Oracle. The required login, stringent password requirements, nosy registration form, and general system instability made this a pretty painful step for me. I’d also like to say that companies that have password requirements that don’t allow symbols (or any other non-standard requirement) have a special place in my heart. Having to recover my password every time I go to your site virtually guarantees I will only go there when I absolutely have to (not often). Anyways, once you have it downloaded you need to install is with maven: mvn install:install-file -Dfile=~/Downloads/ojdbc6.jar -DgroupId=com.oracle -DartifactId=ojdbc6 -Dversion=11.2.0.3 -Dpackaging=jar -DgeneratePom=true Here comes the fun part. You need to create an osgi wrapper for the driver to install it in roo. Otherwise, roo cannot see the driver. Create a new folder and put the contents of the oracle roo addon pom gist I created. Now build it with maven. You may want to change some of the artifact ids and dependencies for your particular situation. mvn package No open a roo shell and execute the following command: osgi install --url file:///Users/me/my-osgi-project/target/the-jar-it-built.jar Now run (in roo): jpa setup --provider HIBERNATE --database ORACLE dependency remove --groupId com.oracle --artifactId ojdbc14 --version 10.2.0.2 dependency add --groupId com.oracle --artifactId ojdbc6 --version 11.2.0.3 database properties set --key database.driverClassName --value oracle.jdbc.OracleDriver database properties set --key database.url --value jdbc:oracle:thin:@%YOUR_CONNECTION_INFO% database properties set --key database.username --value %YOUR_USERNAME% database properties set --key database.password --value %YOUR_PASSWORD% database reverse engineer --schema %YOUR_SCHEMA% --package ~.domain If you have any package loading exceptions when running the reverse engineer command you can uninstall the osgi bundle, set the package to optional in the osgi pom in the IncludedPackages tag (javax.some.package.*;resolution:=optional) rebuild, then reinstall in roo.

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  • Aggregating Excel cell contents that match a label [migrated]

    - by Josh
    I'm sure this isn't a terribly difficult thing, but it's not the type of question that easily lends itself to internet searches. I've been assigned a project for work involving a complex spreadsheet. I've done the usual =SUM and other basic Excel formulas, and I've got enough coding background that I'm able to at least fudge my way through VBA, but I'm not certain how to proceed with one part of the task. Simple version: On Sheet 1 I have a list of people (one on each row, person's name in column A), on sheet 2 I have a list of groups (one on each row, group name in column A). Each name in Sheet 1 has its own row, and I have a "Data Validation" dropdown menu where you choose the group each person belongs to. That dropdown is sourced from Sheet 2, where each group has a row. So essentially the data validation source for Sheet 1's "Group" column is just "=Sheet2!$a1:a100" or whatever. The problem is this: I want each group row in Sheet 2 to have a formula which results in a list of all the users which have been assigned to that group on Sheet 1. What I mean is something the equivalent of "select * from PeopleTab where GROUP = ThisGroup". The resulting cell would just stick the names together like "Bob Smith, Joe Jones, Sally Sanderson" I've been Googling for hours but I can't think of a way to phrase my search query to get the results I want. Here's an example of desired result (Dash-delimited. Can't find a way to make it look nice, table tags don't seem to work here): (Sheet 1) Bob Smith - Group 1 (selected from dropdown) Joe Jones - Group 2 (selected from dropdown) Sally Sanderson - Group 1 (selected from dropdown) (Sheet 2) Group 1 - Bob Smith, Sally Sanderson (result of formula) Group 2 - Joe Jones (result of formula) What formula (or even what function) do I use on that second column of sheet 2 to make a flat list out of the members of that group?

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