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  • At what point is asynchronous reading of disk I/O more efficient than synchronous?

    - by blesh
    Assuming there is some bit of code that reads files for multiple consumers, and the files are of any arbitrary size: At what size does it become more efficient to read the file asynchronously? Or to put it another way, how small must a file be for it to be faster just to read it synchronously? I've noticed (and perhaps I'm incorrect) that when reading very small files, it takes longer to read them asynchronously than synchronously (in particular with .NET). I'm assuming this has to do with set up time for things like I/O Completion Ports, threads, etc. Is there any rule of thumb to help out here? Or is it dependent on the system and the environment?

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  • Tomcat + Spring + CI workflow

    - by ex3v
    We're starting our very first project with Spring and java web stack. This project will be mainly about rewriting quite large ERP/CRM from Zend Framework to Java. Important factor in my question is that I come from php territory, where things (in terms of quality) tend to look different than in java world. Fatcs: there will be 2-3 developers, at least one of developers uses Windows, rest uses Linux, there is one remote linux-based machine, which should handle test and production instances, after struggling with buggy legacy code, we want to introduce good programming and development practices (CI, tests, clean code and so on) client: internal, frequent business logic changes, scrum, daily deployments What I want to achieve is good workflow on as many development stages as possible (coding - commiting - testing - deploying). The problem is that I've never done this before, so I don't know what are best practices to do this. What I have so far is: developers code locally, there is vagrant instance on every development machine, managed by puppet. It contains the same linux, jenkins and tomcat versions as production machine, while coding, developer deploys to vagrant machine, after local merge to test branch, jenkins on vagrant handles tests, when everything is fine, developer pushes commits and merges jenkins on remote machine pulls commit from test branch, runs tests and so on, if everything looks green, jenkins deploys to test tomcat instance Deployment to production is manual (altough it can be done using helping scripts) when business logic is tested by other divisions and everything looks fine to client. Now, the real question: does above make any sense? Things that I'm not sure about: Remote machine: won't there be any problems with two (or even three, as jenkins might need one) instances of same app on tomcat? Using vagrant to develop on php environment is just vise. Isn't this overkill while using Tomcat? I mean, is there higher probability that tomcat will act the same on every machine? Is there sense of having local jenkins on vagrant?

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  • Quick Tip - Speed a Slow Restore from the Transaction Log

    - by KKline
    Here's a quick tip for you: During some restore operations on Microsoft SQL Server, the transaction log redo step might be taking an unusually long time. Depending somewhat on the version and edition of SQL Server you've installed, you may be able to increase performance by tinkering with the readahead performance for the redo operations. To do this, you should use the MAXTRANSFERSIZE parameter of the RESTORE statement. For example, if you set MAXTRANSFERSIZE=1048576, it'll use 1MB buffers. If you...(read more)

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  • How exactly to implement multiple threads in a game

    - by xerwin
    So I recently started learning Java, and having a interest in playing games as well as developing them, naturally I want to create game in Java. I have experience with games in C# and C++ but all of them were single-threaded simple games. But now, I learned how easy it is to make threads in Java, I want to take things to the next level. I started thinking about how would I actually implement threading in a game. I read couple of articles that say the same thing "Usually you have thread for rendering, for updating game logic, for AI, ..." but I haven't (or didn't look hard enough) found example of implementation. My idea how to make implementation is something like this (example for AI) public class AIThread implements Runnable{ private List<AI> ai; private Player player; /*...*/ public void run() { for (int i = 0; i < ai.size(); i++){ ai.get(i).update(player); } Thread.sleep(/* sleep until the next game "tick" */); } } I think this could work. If I also had a rendering and updating thread list of AI in both those threads, since I need to draw the AI and I need to calculate the logic between player and AI(But that could be moved to AIThread, but as an example) . Coming from C++ I'm used to do thing elegantly and efficiently, and this seems like neither of those. So what would be the correct way to handle this? Should I just keep multiple copies of resources in each thread or should I have the resources on one spot, declared with synchronized keyword? I'm afraid that could cause deadlocks, but I'm not yet qualified enough to know when a code will produce deadlock.

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  • Ubuntu 13.XX unable to mount USB HDD. Tried everything. I/O error boot sector/file system

    - by XaviGG
    I know that there are many posts related but none of them helped me. I will jump to the last test because it is the one that should work, but it does not. An external HDD with single partition slow NTFS formatted in Windows, empty and clean. Checked for errors, it tells that not errors where found. Moving to Ubutnu 13.04... Gparted throws the first error when trying to read the disk: Input/output error It appears as unknown the content of the disk. Unable to create partition table or format it, getting the same error when trying. If I try to mount it in the terminal it tells me the same, specifying that also there is an I/O error reading the boot sector. I have this problem since I upgraded (always with fresh install) to 13.04. I thought it will be solved by the 13.10 but it has the same behavior. I tried with two different HDD (HD and SSHD) that work perfectly in Windows 7. In 13.04 at least I got a trying of mounting where the icon of the drive started showing and disappearing until finally it disappeared. But now it doesn't even try. Possible causes: -The HDD was my old main HDD, so it had WIN,RECOVERY,SYSTEM,UBU,SWAP partitions. Maybe the way or place where the partition table is defined is not the best for an external HDD but I don't know a lot in that topic. I would appreciate a lot if someone can give me a guideline to convert one of these HDD in a working external HDD. No files to recover, nothing to care about. Just format completely the disk and be able to use it for storing backups without having to move the files first to the windows partition, load windows and then copy them to the external HDD. Because I want to use a file comparator for the backups. Thanks a lot Edit 1: I found an option in Windows to convert it to a dynamic HDD that warns me that I wont be able to run O.S. after changing. I suppose that is what I need because in the current mode I cannot safely extract it. But it tells me an error that it couldn't change the mode.

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  • Is Akka a good solution for a concurrent pipeline/workflow problem?

    - by herpylderp
    Disclaimer: I am brand new to Akka and the concept of Actors/Event-Driven Architectures in general. I have to implement a fairly complex problem where users can configure a "concurrent pipeline": Pipeline: consists of 1+ Stages; all Stages execute sequentially Stage: consists of 1+ Tasks; all Tasks execute in parallel Task: essentially a Java Runnable As you can see above, a Task is a Runnable that does some unit of work. Tasks are organized into Stages, which execute their Tasks in parallel. Stages are organized into the Pipeline, which executes its Stages sequentially. Hence if a user specifies the following Pipeline: CrossTheRoadSafelyPipeline Stage 1: Look Left Task 1: Turn your head to the left and look for cars Task 2: Listen for cars Stage 2: Look right Task 1: Turn your head to the right and look for cars Task 2: Listen for cars Then, Stage 1 will execute, and then Stage 2 will execute. However, while each Stage is executing, it's individual Tasks are executing in parallel/at the same time. In reality Pipelines will become very complicated, and with hundreds of Stages, dozens of Tasks per Stage (again, executing at the same time). To implement this Pipeline I can only think of several solutions: ESB/Apache Camel Guava Event Bus Java 5 Concurrency Actors/Akka Camel doesn't seem right because its core competency is integration not synchrony and orchestration across worker threads. Guava is great, but this doesn't really feel like a subscriber/publisher-type of problem. And Java 5 Concurrency (ExecutorService, etc.) just feels too low-level and painful. So I ask: is Akka a strong candidate for this type of problem? If so, how? If not, then why, and what is a good candidate?

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  • How many disk should I use to meed the capacity and IOPS need?

    - by facebook-100005613813158
    An application needs 1.6 TB of storage capacity and performs 1000 IOPS. How many disks are required to meet the application requirement and offer acceptable response time? The disk specifications are as follows: - Drive capacity = 100 GB - 15K RPM - Each disk can perform 50 IOPS 4 candidate , 10,12,16,20, which one is the most likely answer? in my opinion,16 disks can only meet the capacity need ,but cannot meet the IOPS need, so ,the right answer should be 20 disks?right?

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  • 2D Image Creator for a video game

    - by user1276078
    I need to make a few images for an arcade video game I'm making in Java. As of right now, I have drawings that animate, but there are two problems. The drawings are horrible, and as a result, the game won't get enough attention. It's a pain to have to change each coordinate for the drawing, as the drawings are fairly complex. I'd like to use images. I feel they could solve my problem. They would look better than the drawings, and it would only have an x and a y coordinate, rather than the many coordinates I need for each drawing. So, in a sense, I have two questions. Would images actually help? Would they solve my 2 problems? I just want to clarify. How would I make these images. I don't think I can copy them off of the internet because I plan on publishing this game. So, is there any software where you can make your own images? (It has to be in an image type that Java can support. I'm working with java). It also, as stated by the header, needs to be a 2D image; not 3D

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  • iPhone in-app purchasing for Ecommerce [closed]

    - by Kyle B.
    This may not be the appropriate location for this, but would like to ask in the hopes an iOS developer with familiarity on the rules and regulations could comment. I would like to develop an iOS app that performs Ecommerce transactions. If I roll my own payment processor, and checkout process: 1) Is this allowed by Apple's rules, and 2) Would I be required to remit 30% of the transaction sale to Apple?

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  • The idea of functionN in Scala / Functionaljava

    - by Luke Murphy
    From brain driven development It turns out, that every Function you’ll ever define in Scala, will become an instance of an Implementation which will feature a certain Function Trait. There is a whole bunch of that Function Traits, ranging from Function1 up to Function22. Since Functions are Objects in Scala and Scala is a statically typed language, it has to provide an appropriate type for every Function which comes with a different number of arguments. If you define a Function with two arguments, the compiler picks Function2 as the underlying type. Also, from Michael Froh's blog You need to make FunctionN classes for each number of parameters that you want? Yes, but you define the classes once and then you use them forever, or ideally they're already defined in a library (e.g. Functional Java defines classes F, F2, ..., F8, and the Scala standard library defines classes Function1, ..., Function22) So we have a list of function traits (Scala), and a list of interfaces (Functional-java) to enable us to have first class funtions. I am trying to understand exactly why this is the case. I know, in Java for example, when I write a method say, public int add(int a, int b){ return a + b; } That I cannot go ahead and write add(3,4,5); ( error would be something like : method add cannot be applied to give types ) We simply have to define an interface/trait for functions with different parameters, because of static typing?

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  • Finding the best practice for a game simulating tool

    - by Tougheart
    I'm studying Java right now, and I'm thinking of this tool as my practice project. The game is "League of Legends" in case anyone knows it, I'm not actually simulating the game as in simulating game play, I'm just trying to create a tool that can compare different champions to each other based on their own abilities and items bought inside the game. The game basics are: Every player has a champion in a team of 5 players playing against another team. Each champion has a different set of abilities (usually 4) that s/he uses to do damage to opposing champions. Each champion gets stronger by buying different items, increasing the attack it deals or decreasing the damage received. What I want to do is to create a tool to be used outside the game enabling players to try out different builds for their champions and compare the figures against other champions they usually fight against. The goal is to enable players get a deeper understanding of the different item combinations (builds) that can be used during the games, instead of trying them out in real games which can be somehow very time consuming. What I'm stuck at is the best practice I should follow to make this possible using Java, I can't figure out which classes should inherit from which, should I make champions and items specs in the code or extracted from other files, specially that I'm talking about hundreds of items and champions to use in that tool. I'm self studying Java, and I don't have much practice at it, so I would really appreciate any broad guidelines regarding this, and sorry if my question doesn't fit here, I tried to follow the rules. English isn't my native language, so I'm really sorry if I wasn't clear enough, I would be more than happy to explain anything that's not understood.

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  • the requested resource is not available [closed]

    - by James Pj
    I have written a Java servlet program and run it through local Tomcat 7, But it was showing following error : HTTP Status 404 - /skypark/registration type Status report message /skypark/registration description The requested resource is not available. Apache Tomcat/7.0.33 I don't know what was the reason for it my Html page is <html> <head> <title> User registration </title> </head> <body> <form action="registration" method="post"> <center> <h2><b>Skypark User Registration</b></h2> <table border="0"> <tr><td> First Name </td><td> <input type="text" name="fname"/></br> </td></tr><tr><td> Last Name </td><td> <input type="text" name="lname"/></br> </td></tr><tr><td> UserName </td><td> <input type="text" name="uname"></br> </td></tr><tr><td> Enter Password </td><td> <input type="password" name="pass"></br> </td></tr><tr><td> Re-Type Password </td><td> <input type="password" name="pass1"></br> </td></tr><tr><td> Enter Email ID </td><td> <input type="email" name="email1"></br> </td></tr><tr><td> Phone Number </td><td> <input type="number" name="phone"> </td></tr><tr><td> Gender<br> </td></tr><tr><td> <input type="radio" name="gender" value="Male">Male</input></br> </td></tr><tr><td> <input type="radio" name="gender" value="Female">Female</input></br> </td></tr><tr><td> Enter Your Date of Birth<br> </td><td> <Table Border=0> <tr> <td> Date </td> <td>Month</td> <td>Year</td> </tr><tr> <td> <select name="date"> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> . . . have some code . . . </table> <input type="submit" value="Submit"></br> </center> </form> </body> </html> My servlet is : package skypark; import skypark.*; import java.io.*; import javax.servlet.*; import javax.servlet.http.*; import java.sql.*; public class Registration extends HttpServlet { public static Connection prepareConnection()throws ClassNotFoundException,SQLException { String dcn="oracle.jdbc.driver.OracleDriver"; String url="jdbc:oracle:thin:@JamesPJ-PC:1521:skypark"; String usname="system"; String pass="tiger"; Class.forName(dcn); return DriverManager.getConnection(url,usname,pass); } public void doPost(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException { resp.setContentType("text/html"); PrintWriter out=resp.getWriter(); try { String phone1,uname,fname,lname,dob,address,city,state,country,pin,email,password,gender,lang,qual,relegion,privacy,hobbies,fav; uname=req.getParameter("uname"); fname=req.getParameter("fname"); lname=req.getParameter("lname"); dob=req.getParameter("date"); address=req.getParameter("address"); city=req.getParameter("city"); state=req.getParameter("state"); country=req.getParameter("country"); pin=req.getParameter("pin"); email=req.getParameter("email1"); password=req.getParameter("password"); gender=req.getParameter("gender"); phone1=req.getParameter("phone"); lang=""; qual=""; relegion=""; privacy=""; hobbies=""; fav=""; int phone=Integer.parseInt(phone1); Connection con=prepareConnection(); String Query="Insert into regdetails values(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)"; PreparedStatement ps=con.prepareStatement(Query); ps.setString(1,uname); ps.setString(2,fname); ps.setString(3,lname); ps.setString(4,dob); ps.setString(5,address); ps.setString(6,city); ps.setString(7,state); ps.setString(8,country); ps.setString(9,pin); ps.setString(10,lang); ps.setString(11,qual); ps.setString(12,relegion); ps.setString(13,privacy); ps.setString(14,hobbies); ps.setString(15,fav); ps.setString(16,gender); int c=ps.executeUpdate(); String query="insert into passmanager values(?,?,?,?)"; PreparedStatement ps1=con.prepareStatement(query); ps1.setString(1,uname); ps1.setString(2,password); ps1.setString(3,email); ps1.setInt(4,phone); int i=ps1.executeUpdate(); if(c==1||c==Statement.SUCCESS_NO_INFO && i==1||i==Statement.SUCCESS_NO_INFO) { out.println("<html><head><title>Login</title></head><body>"); out.println("<center><h2>Skypark.com</h2>"); out.println("<table border=0><tr>"); out.println("<td>UserName/E-Mail</td>"); out.println("<form action=login method=post"); out.println("<td><input type=text name=uname></td>"); out.println("</tr><tr><td>Password</td>"); out.println("<td><input type=password name=pass></td></tr></table>"); out.println("<input type=submit value=Login>"); out.println("</form></body></html>"); } else { out.println("<html><head><title>Error!</title></head><body>"); out.println("<center><b>Given details are incorrect</b>"); out.println(" Please try again</center></body></html>"); RequestDispatcher rd=req.getRequestDispatcher("registration.html"); rd.include(req,resp); return; } } catch(Exception e) { out.println("<html><head><title>Error!</title><body>"); out.println("<b><i>Unable to process try after some time</i></b>"); out.println("</body></html>"); RequestDispatcher rd=req.getRequestDispatcher("registration.html"); rd.include(req,resp); return; } out.flush(); out.close(); } } And the web.xml file is <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0" metadata-complete="true"> <servlet> <servlet-name>reg</servlet-name> <servlet-class>skypark.Registration</servlet-class> </servlet> <servlet-mapping> <servlet-name>reg</servlet-name> <url-pattern>/registration</url-pattern> </servlet-mapping> This i kept in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\WEB_INF\web.xml and servlet class in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\WEB_INF\classes\skypark and registration.html in C:\Program Files\Apache Software Foundation\Tomcat 7.0\webapps\skypark\ if any mistake in this makes above error means please help me.Thanks in advance....

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  • Reading input all together or in steps?

    - by nischayn22
    For many programming quizzes we are given a bunch of input lines and we have to process each input , do some computation and output the result. My question is what is the best way to optimize the runtime of the solution ? Read all input, store it (in array or something) ,compute result for all of them, finally output it all together. or 2. Read one input, compute the result, output the result and so on for each input given.

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  • How to identify web development benchmarking questions? [closed]

    - by GenericJam
    I am in my final year of college and I have to put forward some sort of thesis for my final year project. The project is a web based attendance system that I am building for the college. I have it about 70% complete in Java. After completing it in Java, the plan is for me to rewrite the server bit in Erlang and then release the bitter rivals in a head to head cage match. The idea being that there is some sort of grounds for comparison. There are a few hurdles along the way, such as me learning Erlang. I understand that a performance comparison like this isn't strictly scientific as there are many factors such as the programmer (myself); the hardware it runs on; etc... but it is meant to be a reasonable comparison of the merits of using Java vs. Erlang for web development. I need help in identifying what the relevant questions are that my project could address. Even though the project scope is fixed, I am trying to shoehorn in some worthwhile scientific inquiries.

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  • The better way to ask for input?

    - by Skippy
    I am wondering which is the best way to go with java code. I need to create a class with simple prompts for input.. I have tried using both classes and cannot work out the particular benefits for each. Is this because I am still in the early stages of programming or are there situations that will occur as it becomes more complex?? import java.util.Scanner; public class myClass { Scanner stdin = new Scanner(System.in); public String getInput(String prompt) { System.out.print(prompt); return stdin.nextLine(); } ... or import java.io.*; public class myClass { public static void main(String[] args) throws IOException { BufferedReader stdin = new BufferedReader (new InputStreamReader (System.in)); System.out.print("Input something: "); String name = stdin.readLine(); I know these examples are showing different methods within these classes, but thought this might serve well for the discussion. I'm really not sure which site is the best to ask this on.

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  • Structuring an input file

    - by Ricardo
    I am in the process of structuring a small program to perform some hydraulic analysis of pipe flow. As I am envisioning this, the program will read an input file, store the input parameters in a suitable way, operate on them and finally output results. I am struggling with how to structure the input file in a sane way; that is, in a way that a human can write it easily and a machine can parse it easily. A sample input file made available to me for a similar program is just a stream of comma-separated numbers that don't make much sense on their own, so that's the scenario I am trying to avoid. Though I am giving the details of my particular problem, I am more interested in general input-file structuring strategies. Is a stream of comma-separated values my best bet? Would I be better off using some sort of key:value structure? I don't know much about this, so any help will probably put me in a better track than I am now.

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  • At what point asynchronous reading of disk I/O is more efficient than synchronous?

    - by blesh
    Assuming there is some bit of code that reads files for multiple consumers, and the files are of any arbitrary size: At what size does it become more efficient to read the file asynchronously? Or to put it another way, how small must a file be for it to be faster just to read it synchronously? I've noticed (and perhaps I'm incorrect) that when reading very small files, it takes longer to read them asynchronously than synchronously (in particular with .NET). I'm assuming this has to do with set up time for things like I/O Completion Ports, threads, etc. Is there any rule of thumb to help out here? Or is it dependent on the system and the environment?

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  • JSR 308 Moves Forward

    - by abuckley
    I am pleased to announce a number of recent milestones for JSR 308, Annotations on Java Types: Adoption of JCP 2.8 Thanks to the agreement of the Expert Group, JSR 308 operates under JCP 2.8 from September 2012. There is a publicly archived mailing list for EG members, and a companion list for anyone who wishes to follow EG traffic by email. There is also a "suggestion box" mailing list where anyone can send feedback to the E.G. directly. Feedback will be discussed on the main EG list. Co-spec lead Prof. Michael Ernst maintains an issue tracker and a document archive. Early-Access Builds of the Reference Implementation Oracle has published binaries for all platforms of JDK 8 with support for type annotations. Builds are generated from OpenJDK's type-annotations/type-annotations forest (notably the langtools repo). The forest is owned by the Type Annotations project. Integration with Enhanced Metadata On the enhanced metadata mailing list, Oracle has proposed support for repeating annotations in the Java language in Java SE 8. For completeness, it must be possible to repeat annotations on types, not only on declarations. The implementation of repeating annotations on declarations is already in the type-annotations/type-annotations forest (and hence in the early-access builds above) and work is underway to extend it to types.

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  • Why am I seeing so many instantiable classes without state?

    - by futlib
    I'm seeing a lot of instantiable classes in the C++ and Java world that don't have any state. I really can't figure out why people do that, they could just use a namespace with free functions in C++, or a class with a private constructor and only static methods in Java. The only benefit I can think of is that you don't have to change most of your code if you later decide that you want a different implementation in certain situations. But isn't that a case of premature design? It could be turned into a class later, when/if it becomes appropriate. Am I getting this wrong? Is it not OOP if I don't put everything into objects (i.e. instantiated classes)? Then why are there so many utility namespaces and classes in the standard libraries of C++ and Java? Update: I've certainly seen a lot examples of this in my previous jobs, but I'm struggling to find open source examples, so maybe it's not that common after all. Still, I'm wondering why people do it, and how common it is.

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  • Separate update and render

    - by NSAddict
    I'm programming a simple Snake in Java. I'm a complete newbie when it comes to Java and Game Developing, so please bear with me ;) Until now, I have been using a UI thread, as well as a update-thread. The update thread just set the position, set the GameObjects, and so on. I didn't think much of concurrency, but now I've come to a problem. I wanted to modify the ArrayList<GameObject>, but it throws a java.util.ConcurrentModificationException. With a little research I found out that this happens because the two threads are trying to access the variables at the same time. But I didn't really find a way to prevent this. I thought about copying the array and swapping them out when the rendering is finished, but I would have to deep-copy them, which isn't really the best solution in my opinion. It probably eats up more CPU resources than a single-threaded game. Are there any other ways to prevent this? Thanks a lot for your help!

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  • How should I implement multiple threads in a game? [duplicate]

    - by xerwin
    This question already has an answer here: Multi-threaded games best practices. One thread for 'logic', one for rendering, or more? 6 answers So I recently started learning Java, and having a interest in playing games as well as developing them, naturally I want to create game in Java. I have experience with games in C# and C++ but all of them were single-threaded simple games. But now, I learned how easy it is to make threads in Java, I want to take things to the next level. I started thinking about how would I actually implement threading in a game. I read couple of articles that say the same thing "Usually you have thread for rendering, for updating game logic, for AI, ..." but I haven't (or didn't look hard enough) found example of implementation. My idea how to make implementation is something like this (example for AI) public class AIThread implements Runnable{ private List<AI> ai; private Player player; /*...*/ public void run() { for (int i = 0; i < ai.size(); i++){ ai.get(i).update(player); } Thread.sleep(/* sleep until the next game "tick" */); } } I think this could work. If I also had a rendering and updating thread list of AI in both those threads, since I need to draw the AI and I need to calculate the logic between player and AI(But that could be moved to AIThread, but as an example) . Coming from C++ I'm used to do thing elegantly and efficiently, and this seems like neither of those. So what would be the correct way to handle this? Should I just keep multiple copies of resources in each thread or should I have the resources on one spot, declared with synchronized keyword? I'm afraid that could cause deadlocks, but I'm not yet qualified enough to know when a code will produce deadlock.

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  • What is wrong with this code for reading binary files? [on hold]

    - by qed
    What is wrong with this code for reading binary files? It compiles OK, but will not print out the file as planned, in fact, it prints nothing at all. #include <iostream> #include <fstream> int main(int argc, const char *argv[]) { if (argc < 2) { ::std::cerr << "usage: " << argv[0] << " <filename>\n"; return 1; } ::std::basic_ifstream<unsigned char> in(argv[1], ::std::ios::binary); unsigned char uc; while (in.get(uc)) { printf("%02X ", uc); } // TODO: error handling, in case the file could not be opened or read return 0; }

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  • ClassFormatError when using javaee:javaee-api

    - by Digambar Daund
    This is my pom.xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>dd</groupId> <artifactId>jee6</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <groupId>dd</groupId> <artifactId>business-tier-impl</artifactId> <name>business-tier-impl</name> <version>0.0.1-SNAPSHOT</version> <packaging>ejb</packaging> <description>business-tier-impl</description> <dependencies> <dependency> <groupId>javax</groupId> <artifactId>javaee-api</artifactId> <version>6.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.testng</groupId> <artifactId>testng</artifactId> <version>5.11</version> <scope>test</scope> <classifier>jdk15</classifier> </dependency> <dependency> <groupId>org.apache.openejb</groupId> <artifactId>openejb-core</artifactId> <version>3.1.2</version> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.6</source> <target>1.6</target> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-ejb-plugin</artifactId> <configuration> <ejbVersion>3.1.2</ejbVersion> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> </plugin> </plugins> </build> </project> Below is the testcase setup methhod: @BeforeClass public void bootContainer() throws Exception { Properties props = new Properties(); props.setProperty(Context.INITIAL_CONTEXT_FACTORY, LocalInitialContextFactory.class.getName()); Context context = new InitialContext(props); service = (HelloService) context.lookup("HelloServiceLocal"); } I get error at line where InitialContext() is created... Apache OpenEJB 3.1 build: 20081009-03:31 http://openejb.apache.org/ INFO - openejb.home = C:\DD\WORKSPACES\jee6\business-tier-impl INFO - openejb.base = C:\DD\WORKSPACES\jee6\business-tier-impl FATAL - OpenEJB has encountered a fatal error and cannot be started: OpenEJB encountered an unexpected error while attempting to instantiate the assembler. java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/resource/spi/ResourceAdapterInternalException . . . FAILED CONFIGURATION: @BeforeClass bootContainer javax.naming.NamingException: Attempted to load OpenEJB. OpenEJB has encountered a fatal error and cannot be started: OpenEJB encountered an unexpected error while attempting to instantiate the assembler.: Absent Code attribute in method that is not native or abstract in class file javax/resource/spi/ResourceAdapterInternalException [Root exception is org.apache.openejb.OpenEJBException: OpenEJB has encountered a fatal error and cannot be started: OpenEJB encountered an unexpected error while attempting to instantiate the assembler.: Absent Code attribute in method that is not native or abstract in class file javax/resource/spi/ResourceAdapterInternalException] at org.apache.openejb.client.LocalInitialContextFactory.init(LocalInitialContextFactory.java:54) at org.apache.openejb.client.LocalInitialContextFactory.getInitialContext(LocalInitialContextFactory.java:41) at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:667) at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288) at javax.naming.InitialContext.init(InitialContext.java:223) at javax.naming.InitialContext.<init>(InitialContext.java:197) at dd.jee6.app.HelloServiceTest.bootContainer(HelloServiceTest.java:26) Caused by: org.apache.openejb.OpenEJBException: OpenEJB has encountered a fatal error and cannot be started: OpenEJB encountered an unexpected error while attempting to instantiate the assembler.: Absent Code attribute in method that is not native or abstract in class file javax/resource/spi/ResourceAdapterInternalException at org.apache.openejb.OpenEJB$Instance.<init>(OpenEJB.java:133) at org.apache.openejb.OpenEJB.init(OpenEJB.java:299) at org.apache.openejb.OpenEJB.init(OpenEJB.java:278) at org.apache.openejb.loader.OpenEJBInstance.init(OpenEJBInstance.java:36) at org.apache.openejb.client.LocalInitialContextFactory.init(LocalInitialContextFactory.java:69) at org.apache.openejb.client.LocalInitialContextFactory.init(LocalInitialContextFactory.java:52) ... 28 more Caused by: java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/resource/spi/ResourceAdapterInternalException at java.lang.ClassLoader.defineClass1(Native Method)

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  • how do I register a custom conversion Service in spring 3 / webflow 2?

    - by nont
    I've been trying to follow this example and using the reference to guide me, but I'm having no luck. I've defined a converter: import org.springframework.binding.convert.converters.StringToObject; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.text.ParseException; import java.util.Date; public class StringToDateTwoWayConverter extends StringToObject { private DateFormat format = null; public StringToDateTwoWayConverter () { super(StringToDateTwoWayConverter.class); format = new SimpleDateFormat("MM/dd/yyyy"); } @Override protected Object toObject(String string, Class targetClass) throws Exception { Date date = null; try { date = format.parse(string); } catch (ParseException e) { e.printStackTrace(); return null; } return date; } @Override protected String toString(Object object) throws Exception { Date date = (Date) object; return format.format(date); } } and a conversionService: import org.springframework.binding.convert.service.DefaultConversionService; import org.springframework.stereotype.Component; @Component("conversionService") public class ApplicationConversionService extends DefaultConversionService { @Override protected void addDefaultConverters() { super.addDefaultConverters(); this.addConverter(new StringToDateTwoWayConverter()); this.addConverter("shortDate", new StringToDateTwoWayConverter()); } } and configured it: <webflow:flow-builder-services id="flowBuilderServices" conversion-service="conversionService" .../> However, upon startup, I'm greeted with this exception: Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name '(inner bean)': Unsatisfied dependency expressed through constructor argument with index 0 of type [org.springframework.core.convert.ConversionService]: Could not convert constructor argument value of type [com.yadayada.converter.ApplicationConversionService] to required type [org.springframework.core.convert.ConversionService]: Failed to convert value of type 'com.yadayada.converter.ApplicationConversionService' to required type 'org.springframework.core.convert.ConversionService'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [com.yadayada.converter.ApplicationConversionService] to required type [org.springframework.core.convert.ConversionService]: no matching editors or conversion strategy found at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:687) at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:195) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:993) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:897) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:270) ... 60 more I'm thoroughly puzzled why its not working. The conversion service implements ConversionService through its base class, so I don't see the problem. Any insight much appreciated!

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  • JavaMail: Could not connect to SMPT server.

    - by javacode
    Hi The following code causes an error. Please help me understand what's wrong. import javax.mail.*; import javax.mail.internet.*; import java.util.*; public class SendMail { public static void main(String [] args)throws MessagingException { SendMail sm=new SendMail(); sm.postMail(new String[]{"[email protected]"},"hi","hello","[email protected]"); } public void postMail( String recipients[ ], String subject, String message , String from) throws MessagingException { boolean debug = false; //Set the host smtp address Properties props = new Properties(); props.put("mail.smtp.host", "webmail.emailmyname.com"); // create some properties and get the default Session Session session = Session.getDefaultInstance(props, null); session.setDebug(debug); // create a message Message msg = new MimeMessage(session); // set the from and to address InternetAddress addressFrom = new InternetAddress(from); msg.setFrom(addressFrom); InternetAddress[] addressTo = new InternetAddress[recipients.length]; for (int i = 0; i < recipients.length; i++) { addressTo[i] = new InternetAddress(recipients[i]); } msg.setRecipients(Message.RecipientType.TO, addressTo); // Optional : You can also set your custom headers in the Email if you Want msg.addHeader("MyHeaderName", "myHeaderValue"); // Setting the Subject and Content Type msg.setSubject(subject); msg.setContent(message, "text/plain"); Transport.send(msg); } } Exception: Exception in thread "main" javax.mail.MessagingException: Could not connect to SMTP host: webmail.emailmyname.com, port: 25, response: 421 at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1694) at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525) at javax.mail.Service.connect(Service.java:291) at javax.mail.Service.connect(Service.java:172) at javax.mail.Service.connect(Service.java:121) at javax.mail.Transport.send0(Transport.java:190) at javax.mail.Transport.send(Transport.java:120) at SendMail.postMail(SendMail.java:45) at SendMail.main(SendMail.java:9)

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