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  • Vector ArrayIndexOutOfBounds

    - by Esmond
    I'm having an ArrayIndexOutofBounds exception with the following code. The exception is thrown at the line where Node nodeJ = vect.get(j) but it does not make sense to me since j is definitely smaller than i and Node nodeI = vect.get(i) does not throw any exception. any help is appreciated. public static Vector join(Vector vect) throws ItemNotFoundException { Vector<Node> remain = vect; for (int i = 1; i < vect.size(); i++) { Node nodeI = vect.get(i); for (int j = 0; j < i; j++) {//traverse the nodes before nodeI Node nodeJ = vect.get(j); if (nodeI.getChild1().getSeq().equals(nodeJ.getSeq())) { nodeI.removeChild(nodeJ); nodeI.setChild(nodeJ); remain.remove(j); } if (nodeI.getChild2().getSeq().equals(nodeJ.getSeq())) { nodeI.removeChild(nodeJ); nodeI.setChild(nodeJ); remain.remove(j); } } } return remain; }

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  • Arrays of different types

    - by Tyler
    Hi - Is it possible to have an array that contains two different types of data? I want to have an array that contains a double and also a string. I attempted: ArrayList<double><String> array; But that didn't work. Sorry for the silly question, but it has been a while since I have used something like this.. Can you refresh my memory on how would I declare and populate such an array? And then to take it a step further, I would like to sort the array by the double if possible? Thanks!

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  • Problem with setVisible (true)

    - by Jessy
    The two examples shown below are same. Both are supposed to produce same result e.g. generate the coordinates of images displayed on JPanel. Example 1, works perfectly (print the coordinates of images), however example 2 returning 0 for the coordinate. I was wondering why because, I have put the setvisible (true) after adding the panel, in both examples. The only difference is that example 1 used extends JPanel and example 2 extends JFrame EXAMPLE 1: public class Grid extends JPanel{ public static void main(String[] args){ JFrame jf=new JFrame(); jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); final Grid grid = new Grid(); jf.add(grid); jf.pack(); Component[] components = grid.getComponents(); for (Component component : components) { System.out.println("Coordinate: "+ component.getBounds()); } jf.setVisible(true); } } EXAMPLE 2: public class Grid extends JFrame { public Grid () { setLayout(new GridBagLayout()); GridBagLayout m = new GridBagLayout(); Container c = getContentPane(); c.setLayout (m); GridBagConstraints con = new GridBagConstraints(); //construct the JPanel pDraw = new JPanel(); ... m.setConstraints(pDraw, con); pDraw.add (new GetCoordinate ()); // call new class to generate the coordinate c.add(pDraw); pack(); setVisible(true); } public static void main(String[] args) { new Grid(); } }

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  • RSA encryption/ Decryption in a client server application

    - by user308806
    Hi guys, probably missing something very straight forward on this, but please forgive me, I'm very naive! Have a client server application where the client identifies its self with an RSA encrypted username & password. Unfortunately I'm getting a "bad padding exception: data must start with zero" when i try to decrypt with the public key on the client side. I'm fairly sure the key is correct as I have tested encrypting with public key then decrypting with private key on the client side with no problems at all. Just seems when I transfer it over the connection it messses it up somehow?! Using PrintWriter & BufferedReader on the sockets if thats of importance. EncodeBASE64 & DecodeBASE64 encode byte[] to 64base and vice versa respectively. Any ideas guys?? Client side: Socket connectionToServer = new Socket("127.0.0.1", 7050); InputStream in = connectionToServer.getInputStream(); DataInputStream dis = new DataInputStream(in); int length = dis.readInt(); byte[] data = new byte[length]; // dis.readFully(data); dis.read(data); System.out.println("The received Data*****************************************"); System.out.println("The length of bits "+ length); System.out.println(data); System.out.println("***********************************************************"); Decryption d = new Decryption(); byte [] ttt = d.decrypt(data); System.out.print(data); String ss = new String(ttt); System.out.println("***********************"); System.out.println(ss); System.out.println("************************"); Server Side: in = connectionFromClient.getInputStream(); OutputStream out = connectionFromClient.getOutputStream(); DataOutputStream dataOut = new DataOutputStream(out); LicenseList licenses = new LicenseList(); String ValidIDs = licenses.getAllIDs(); System.out.println(ValidIDs); Encryption enc = new Encryption(); byte[] encrypted = enc.encrypt(ValidIDs); byte[] dd = enc.encrypt(ValidIDs); String tobesent = new String(dd); //byte[] rsult = enc.decrypt(dd); //String tt = String(rsult); System.out.println("The sent data**********************************************"); System.out.println(dd); String temp = new String(dd); System.out.println(temp); System.out.println("*************************************************************"); //BufferedWriter bf = new BufferedWriter(OutputStreamWriter(out)); //dataOut.write(ValidIDs.getBytes().length); dataOut.writeInt(ValidIDs.getBytes().length); dataOut.flush(); dataOut.write(encrypted); dataOut.flush(); System.out.println("********Testing**************"); System.out.println("Here are the ids:::"); System.out.println(licenses.getAllIDs()); System.out.println("**********************"); //bw.write("it is working well\n");

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  • Help in debugging the string concatenation code

    - by mithun1538
    I have a code to concatenate strings. However, for some reason, the final string is not a combination of the required strings. Consider the following code : //cusEmail is of type String[] String toList = ""; for(i=0; i < cusEmail.length - 1; i++) { toList.concat(cusEmail[i]); toList.concat("; "); System.out.println(cusEmail[i]); } toList.concat(cusEmail[i]); System.out.println(toList); The first sout statement displays the strings in cusEmail[i] correctly. However, once concatenated, the second sout displays a blank / empty. Any reason for this? Am i concatenating it correctly?

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  • Changing order of children of an SWT Composite

    - by Alexey Romanov
    In my case I have two children of a SashForm, but the question applies to all Composites and different layouts. class MainWindow { Sashform sashform; Tree child1 = null; Table child2 = null; MainWindow(Shell shell) { sashform = new SashForm(shell, SWT.NONE); } // Not called from constructor because it needs data not available at that time void CreateFirstChild() { ... Tree child1 = new Tree(sashform, SWT.NONE); } void CreateSecondChild() { ... Table child2 = new Table(sashform, SWT.NONE); } } I don't know in advance in what order these methods will be called. How can I make sure that child1 is placed on the left, and child2 on the right? Alternately, is there a way to change their order as children of sashform after they are created? Currently my best idea is to put in placeholders like this: class MainWindow { Sashform sashform; private Composite placeholder1; private Composite placeholder2; Tree child1 = null; Table child2 = null; MainWindow(Shell shell) { sashform = new SashForm(shell, SWT.NONE); placeholder1 = new Composite(sashform, SWT.NONE); placeholder2 = new Composite(sashform, SWT.NONE); } void CreateFirstChild() { ... Tree child1 = new Tree(placeholder1, SWT.NONE); } void CreateSecondChild() { ... Table child2 = new Table(placeholder2, SWT.NONE); } }

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  • Is there a useDirtyFlag option for Tomcat 6 cluster configuration?

    - by kevinjansz
    In Tomcat 5.0.x you had the ability to set useDirtyFlag="false" to force replication of the session after every request rather than checking for set/removeAttribute calls. <Cluster className="org.apache.catalina.cluster.tcp.SimpleTcpCluster" managerClassName="org.apache.catalina.cluster.session.SimpleTcpReplicationManager" expireSessionsOnShutdown="false" **useDirtyFlag="false"** doClusterLog="true" clusterLogName="clusterLog"> ... The comments in the server.xml stated this may be used to make the following work: <% HashMap map = (HashMap)session.getAttribute("map"); map.put("key","value"); %> i.e. change the state of an object that has already been put in the session and you can be sure that this object still be replicated to the other nodes in the cluster. According to the Tomcat 6 documentation you only have two "Manager" options - DeltaManager & BackupManager ... neither of these seem to allow this option or anything like it. In my testing the default setup: <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/> where you get the DeltaManager by default, it's definitely behaving as useDirtyFlag="true" (as I'd expect). So my question is - is there an equivalent in Tomcat 6? Looking at the source I can see a manager implementation "org.apache.catalina.ha.session.SimpleTcpReplicationManager" which does have the useDirtyFlag but the javadoc comments in this state it's "Tomcat Session Replication for Tomcat 4.0" ... I don't know if this is ok to use - I'm guessing not as it's not mentioned in the main cluster configuration documentation.

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  • Using Comparable to compare objects and sorting them in a TreeMap

    - by arjacsoh
    II cannot understand how should the natural ordering of class be "consistent with equals" when implementing the Comparable interface. I deteted a flaw in my program and therefore I deteced that in the documentantion of the interface Comparable. My problem is that although two Objects are considered as distinct on the base of equals method, the TreeMap structure treats them as equal and consequently does not accept the second insert. The sample code is: public class Car implements Comparable<Car> { int weight; String name; public Car(int w, String n) { weight=w; name=n; } public boolean equals(Object o){ if(o instanceof Car){ Car d = (Car)o; return ((d.name.equals(name)) && (d.weight==weight)); } return false; } public int hashCode(){ return weight/2 + 17; } public String toString(){ return "I am " +name+ " !!!"; } public int compareTo(Car d){ if(this.weight>d.weight) return 1; else if(this.weight<d.weight) return -1; else return 0; } /*public int compareTo(Car d){ return this.name.compareTo(d.name); }*/ } public static void main(String[] args) { Car d1 = new Car(100, "a"); Car d2 = new Car(110, "b"); Car d3 = new Car(110, "c"); Car d4 = new Car(100, "a"); Map<Car, Integer> m = new HashMap<Car, Integer>(); m.put(d1, 1); m.put(d2, 2); m.put(d3, 3); m.put(d4, 16); for(Map.Entry<Car, Integer> me : m.entrySet()) System.out.println(me.getKey().toString() + " " +me.getValue()); TreeMap<Car, Integer> tm = new TreeMap<Car, Integer>(m); System.out.println("After Sorting: "); for(Map.Entry<Car, Integer> me : tm.entrySet()) System.out.println(me.getKey().toString() + " " +me.getValue()); } The output is : I am a !!! 16 I am c !!! 3 I am b !!! 2 After Sorting: I am a !!! 16 I am c !!! 2 That is, that the object c has replaced (somewhat) object b. If I comment the original equals method and uncomment the second equals method, which compares the objects according name, the output is the expected: I am a !!! 16 I am c !!! 3 I am b !!! 2 After Sorting: I am a !!! 16 I am b !!! 2 I am c !!! 3 Why does it come around in this way and what should I alter in order to insert and sort different objects with some attributes of equal value in a TreeMap?

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  • Logic for controll concurrent in block/method

    - by Hlex
    1)My environment is web application, I develop servlet to receive request. A) In some block/method i want to control concurrent to not greater than 5 B) if there are 5 request in that block , the new coming must wait up to 60 second then throws error C) if there are sleep/waiting request more then 30, the 31th request will be throwed an error How I do this? 2)(Optional Question) from above I have to distribute control logic to all clustered host. I plan to use hazelcast to share the control logic (e.g. current counter) I see they provide BlockingQueue & ExectorService but I have no idea how to use in my case. Please recommend if you have idea.

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  • jQuery, get table cell at specific index

    - by Jarek Waliszko
    Hello, I know that I can get first or last table cell (ex for last row) using jquery expression like below: first cell: $('#table tr:last td:first') or last cell: $('#table tr:last td:last') Can I get cell at specific index, for example index 2, using similliar expression: ex: $('#table tr:last td:[2]')... Regards.

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  • How to set an empty value using XPath?

    - by Ricardo
    Using this xml example: <templateitem itemid="5"> <templateitemdata>%ARN%</templateitemdata> </templateitem> <templateitem itemid="6"> <templateitemdata></templateitemdata> </templateitem> I am using XPath to get and set Node values. The code I am using to get the nodes is: private static Node ***getNode***(Document doc, String XPathQuery) throws XPathExpressionException { XPath xpath = XPathFactory.newInstance().newXPath(); XPathExpression expr = xpath.compile(XPathQuery); Object result = expr.evaluate(doc, XPathConstants.NODESET); NodeList nodes = (NodeList) result; if(nodes != null && nodes.getLength() >0) return nodes.item(0); throw new XPathExpressionException("No node list found for " + XPathQuery); } To get %ARN% value: "//templateitem[@itemid=5]/templateitemdata/text()" and with the getNode method I can get the node, and then call the getNodeValue(). Besides getting that value, I would like to set templateitemdata value for the "templateitem[@itemid=6]" since its empty. But the code I use can't get the node since its empty. The result is null. Do you know a way get the node so I can set the value?

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  • Resized image degrades in quality.

    - by Venkats
    I resized an image using Java2D Graphics class. But it doesn't look right. BufferedImage resizedImage = new BufferedImage(IMG_WIDTH, IMG_HEIGHT, type); Graphics2D g = resizedImage.createGraphics(); g.drawImage(originalImage, 0, 0, IMG_WIDTH, IMG_HEIGHT, null); g.dispose(); Is it possible to scale an image without introducing artifacts?

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  • Update database settings in properties file in Spring

    - by mvg
    Hi all, I am trying to create a Database Manager page which shows the database details on page load and updates the database settings when the user press submit I followed this tutorial and set the database settings in properties file. I managed to update the database settings in properties file programmatically. When I retrieved the database settings using the following code DriverManagerDataSource databaseSource = (DriverManagerDataSource)context.getBean("dataSource"); databaseSource.getUsername(); I managed to get the old value and unable to get the new value This is the mapping in applicationContext.xml file <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="location"> <value>classpath:/bundle/database.properties</value> </property> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="${jdbc.driverClassName}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> </bean> I checked the properties file and found it to be updated with the latest input. What am I missing? Thanks in advance P.S I am using JSF1.2 with Spring 3 Update Just making my requirement simple. I am creating a setparate dbsettings page, so that when user wishes to connect to different database he/she can just enter the details in dbsettings page and connect

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  • ExecutorService memory leak on exception

    - by TofuBeer
    I am having a hard time tracking this down since the profiler keeps crashing (hotspot error). Before I go too deep into figuring it out I'd like to know if I really have a problem or not :-) I have a few thread pools created via: Executors.newFixedThreadPool(10); The threads connect to different web sites and, on occasion, I get connection refused and wind up throwing an exception. When I later on call Future.get() to get the result it will then catch the ExecutionException that wraps the exception that was thrown when the connection could not be made. The program uses a fairly constant amount of memory up until the point in time that the exceptions get thrown (they tend to happen in batches when a particular site is overloaded). After that point the memory again remains constant but at a higher level. So my question is along the lines of is the memory behaviour (reported by "top" on Unix) expected because the exceptions just triggered something or do I probably have an actual leak that I'll need to track down? Additionally when Future.get() throws an exception is there anything else I need to do besides catch the exception (such as call Future.cancel() on it)?

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  • Available message types in JMS?

    - by Caylem
    This is based on a past exam question. The question is asking to describe the four types of message available using JMS. The problem is it says the four, not just four. So it assumes their is only four, no more no less. However according to this site their seems to be five; streams maps text objects bytes *Another book states that XML is another potential type in future versions of JMS. Is XML already available? Am I missing something or is the question just wrong? Thanks.

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  • Is selling a "website screen scraper" illegal?

    - by Yatendra Goel
    I have coded a "website screen scraper" and want to sell it commercially. I know that webpages scraped by the screen scraper are restricted to be scraped by the webmaser of that website. The robots.txt file of the website says that its webpages must not be scraped. So my question is whether selling that screen scraper is a crime or using that screen scraper is a crime in legal terms. I know that this question is related to law but I thought the software experts on SO must also have answer to this question.

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  • 500 Worker Threads, what kind of thread pool?

    - by Submerged
    I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing. ExecutorService es = Executors.newFixedThreadPool(list.size()+1); for (int i = 0; i < list.size(); i++) { es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects } The code that is executing is really simple and basically just this class aThread extends Thread { public void run(){ while(true){ Thread.sleep(ONE_MINUTE); //Lots of computation every minute } } } I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful! Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"

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  • How do I execute a sequence of servlets?

    - by Legend
    I have some servlets that act as individual URLs for populating a database for some dummy testing. Something of the form: public class Populate_ServletName extends HttpServlet { public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { resp.setContentType("text/plain"); //Insert records //Print confirmation } } I have about 6 such servlets which I want to execute in a sequence. I was thinking of using setLocation to set the next page to be redirected but was not sure if this is the right approach because the redirects should happen after the records have been inserted. Specifically, I am looking for something like this: public class Populate_ALL extends HttpServlet { public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { resp.setContentType("text/plain"); //Call Populate_1 //Call Populate_2 //Call Populate_3 //... } } Any suggestions?

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  • Source code versioning with comments (organizational practice) - leave or remove?

    - by ADTC
    Before you start admonishing me with "DON'T DO IT," "BAD PRACTICE!" and "Learn to use proper source code control", please hear me out first. I am fully aware that the practice of commenting out old code and leaving it there forever is very bad and I hate such practice myself. But here's the situation I'm in. A few months ago I joined a company as software developer. I had worked in the company for few months as an intern, about a year before joining recently. Our company uses source code version control (CVS) but not properly. Here's what happened both in my internship and my current permanent position. Each time I was assigned to work on a project (legacy, about 8-10 years old). Instead of creating a CVS account and letting me check out code and check in changes, a senior colleague exported the code from CVS, zipped it up and passed it to me. While this colleague checks in all changes in bulk every few weeks, our usual practice is to do fine-grained versioning in the actual source code itself (each file increments in versions independent from the rest). Whenever a change is made to a file, old code is commented out, new code entered below it, and this whole section is marked with a version number. Finally a note about the changes is placed at the top of the file in a section called Modification History. Finally the changed files are placed in a shared folder, ready and waiting for the bulk check-in. /* * Copyright notice blah blah * Some details about file (project name, file name etc) * Modification History: * Date Version Modified By Description * 2012-10-15 1.0 Joey Initial creation * 2012-10-22 1.1 Chandler Replaced old code with new code */ code .... //v1.1 start //old code new code //v1.1 end code .... Now the problem is this. In the project I'm working on, I needed to copy some new source code files from another project (new in the sense that they didn't exist in destination project before). These files have a lot of historical commented out code and comment-based versioning including usually long or very long Modification History section. Since the files are new to this project I decided to clean them up and remove unnecessary code including historical code, and start fresh at version 1.0. (I still have to continue the practice of comment-based versioning despite hating it. And don't ask why not start at version 0.1...) I have done similar something during my internship and no one said anything. My supervisor has seen the work a few times and didn't say I shouldn't do such clean-up (if at all it was noticed). But a same-level colleague saw this and said it's not recommended as it may cause downtime in the future and increase maintenance costs. An example is when changes are made in another project on the original files and these changes need to be propagated to this project. With code files drastically different, it could cause confusion to an employee doing the propagation. It makes sense to me, and is a valid point. I couldn't find any reason to do my clean-up other than the inconvenience of a ridiculously messy code. So, long story short: Given the practice in our company, should I not do such clean-up when copying new files from project to project? Is it better to make changes on the (copy of) original code with full history in comments? Or what justification can I give for doing the clean-up? PS to mods: Hope you allow this question some time even if for any reason you determine it to be unfit in SO. I apologize in advance if anything is inappropriate including tags.

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