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  • How to debug JBoss out of memory problem?

    - by user561733
    Hello, I am trying to debug a JBoss out of memory problem. When JBoss starts up and runs for a while, it seems to use memory as intended by the startup configuration. However, it seems that when some unknown user action is taken (or the log file grows to a certain size) using the sole web application JBoss is serving up, memory increases dramatically and JBoss freezes. When JBoss freezes, it is difficult to kill the process or do anything because of low memory. When the process is finally killed via a -9 argument and the server is restarted, the log file is very small and only contains outputs from the startup of the newly started process and not any information on why the memory increased so much. This is why it is so hard to debug: server.log does not have information from the killed process. The log is set to grow to 2 GB and the log file for the new process is only about 300 Kb though it grows properly during normal memory circumstances. This is information on the JBoss configuration: JBoss (MX MicroKernel) 4.0.3 JDK 1.6.0 update 22 PermSize=512m MaxPermSize=512m Xms=1024m Xmx=6144m This is basic info on the system: Operating system: CentOS Linux 5.5 Kernel and CPU: Linux 2.6.18-194.26.1.el5 on x86_64 Processor information: Intel(R) Xeon(R) CPU E5420 @ 2.50GHz, 8 cores This is good example information on the system during normal pre-freeze conditions a few minutes after the jboss service startup: Running processes: 183 CPU load averages: 0.16 (1 min) 0.06 (5 mins) 0.09 (15 mins) CPU usage: 0% user, 0% kernel, 1% IO, 99% idle Real memory: 17.38 GB total, 2.46 GB used Virtual memory: 19.59 GB total, 0 bytes used Local disk space: 113.37 GB total, 11.89 GB used When JBoss freezes, system information looks like this: Running processes: 225 CPU load averages: 4.66 (1 min) 1.84 (5 mins) 0.93 (15 mins) CPU usage: 0% user, 12% kernel, 73% IO, 15% idle Real memory: 17.38 GB total, 17.18 GB used Virtual memory: 19.59 GB total, 706.29 MB used Local disk space: 113.37 GB total, 11.89 GB used

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  • What is the effect of final variable declaration in methods?

    - by Finbarr
    Classic example of a simple server: class ThreadPerTaskSocketServer { public static void main(String[] args) throws IOException { ServerSocket socket = new ServerSocket(80); while (true) { final Socket connection = socket.accept(); Runnable task = new Runnable() { public void run() { handleRequest(connection); } }; new Thread(task).start(); } } } Why should the Socket be declared as final? Is it because the new Thread that handles the request could refer back to the socket variable in the method and cause some sort of ConcurrentModificationException?

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  • How to export EclipseLink objects to XML

    - by Raven
    Hi, is there an easy approach to store my model, which I use with EclipseLink, in XML files? I want to implement an export functionality in my program and I was wondering if this can be done with eclipselink or with any other framework. Thanks

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  • How to get JTree expanded?

    - by Dzmitry Zhaleznichenka
    I have a wizard with several screens where user has to fill his/her details for further processing. At the second screen I have a radio group with three radio buttons that enable additional elements. To proceed, user has to choose one of them. When user selects third button, single-selection JTree filled in with data enables and user has to select an option from it. Then user has to press "Next" to get to next screen. The option he\she had selected is stored as a TreePath. So far so good. My problem is the following. If the user wants to come back from the following screen to the screen with a JTree, I want to provide him\her with the JTree expanded to the option that had been selected and to highlight the option. However, whatsoever I try to do for that (any combinations of expandPath, scrollPathToVisible, addSelectionPath, makeVisible) always provides me with a collapsed tree. I try to expand both leaves and nodes. My code looks like this: rbProcessJTree.setSelected(isProcessJTree()); if (null != getSelectedTablePath()){ trTables.addSelectionPath(getSelectedTablePath()); trTables.expandPath(getSelectedTablePath()); trTables.scrollPathToVisible(getSelectedTablePath()); } When setSelected() is called, state change listener is invoked that enables JTree. The model is loaded during the form initialization. Each time I switch between screens, I save the input data from previous screen and dispose it. Then, when I need to open previous screen back, I save data from the following screen, dispose it, load data to this screen and show it. So each time the screen is generating from scratch. Could you please explain, what sequence of operations has to be done to get JTree expanded in a newly created form,with data model loaded and selection path provided?

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  • List of items with same values

    - by user559780
    I'm creating a list of items from a file BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("H:/temp/data.csv"))); try { List<Item> items = new ArrayList<Item>(); Item item = new Item(); String line = null; while ((line = reader.readLine()) != null) { String[] split = line.split(","); item.name = split[0]; item.quantity = Integer.valueOf(split[1]); item.price = Double.valueOf(split[2]); item.total = item.quantity * item.price; items.add(item); } for (Item item2 : items) { System.out.println("Item: " + item2.name); } } catch (IOException e) { reader.close(); e.printStackTrace(); } Problem is the list is displaying the last line in the file as the value for all items.

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  • Free JVM profilers for websites

    - by 2Real
    I'm looking for a JVM profiler (preferably open source) so I can look at the heap and cpu usage of my personal website. I've used Lambda Probe, and I like it because it provides a web interface for my remote Unix computer that has no display. I was wondering what else is available Thanks,

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  • Create automatically only getters in Eclipse

    - by lerad
    In Eclipse is it possible to create automatically Getters and Setters for a field. But I have a lot of private fields for which only getters should exist. Is somewhere in Eclipse a "create Getters" Function which does not create setters too? Well, it is not so much work to write getters, but doing it automatically would be nice :) Thank you, lerad

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  • Junit 4 test suite and individual test classes

    - by Hypnus
    I have a JUnit 4 test suite with BeforeClass and AfterClass methods that make a setup/teardown for the following test classes. What I need is to run the test classes also by them selves, but for that I need a setup/teardown scenario (BeforeClass and AfterClass or something like that) for each test class. The thing is that when I run the suite I do not want to execute the setup/teardown before and after each test class, I only want to execute the setup/teardown from the test suite (once). Is it possible ? Thanks in advance.

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  • inter servlet communication

    - by mithun1538
    Hello everyone, I have two servlets: LoginServlet and MailServlet. LoginServlet queries a mysql table using jdbc to get a string(eMail). What I want is to forward this string to MailServlet which in turn will send an email to that e-mail ID sent by LoginServlet. My question is how do I call and send the variable eMail to MailServlet, from LoginServlet? I thought of creating an instance of the MailServlet as : MailServlet servlet = new MailServlet(); And then use the servlet object to call the function doGet() in MailServlet. But I am feeling that there is some error in this as this is not the right way to call a servlet. So how do I call and pass a variable to MailServlet?

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  • JButton and next/previous object of treemap

    - by supacat
    I have this problem: 1) There are objects placed in the TreeMap through the JTextField. (Phonebook-like program). 2)There are buttons that implement view of available records in TreeMap. When you click on these buttons next / previous available objects of TreeMap displaying in JTextField. (scroll through the available records). I tried this code, but I didn't work :/ btn[4].addActionListener(new ActionListener(){ Iterator iter = tree.keySet().iterator(); public void actionPerformed(ActionEvent e) { if (iter.hasNext()){ String str = iter.next().toString(); fldFio.setText(str); fldNumber.setText(tree.get(str)); } } });

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  • How to copy an object by value, not by reference

    - by Blankman
    I want to make a copy of an object, then after some logic, re-assign the original object the value of the copy. example: User userCopy = //make a copy foreach(...) { user.Age = 1; user.ID = -1; UserDao.Update(user) user = userCopy; } I don't want a copy by reference, it has to be a copy by value. The above is just a sample, not how I really want to use it but I need to learn how to copy by value.

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  • query on display tag

    - by sarah
    Hi, I have the following code to display <display:table name="sessionScope.userList" id="userList" export="false" pagesize="1"> <display:column title="Select" style="width: 90px;"> <input type="checkbox" name="optionSelected" value=""/> </display:column> <display:column property="userName" sortable="false" title="UserName" paramId="userName" style="width: 150px; text-align:center" href="#"/> </display:table> On click of the checkbox i need to get the corresponding row value that is the username how would i get that?

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  • select multiple double side

    - by Mercer
    hello, i want to do a select multiple double side like this : http://www.senamion.com/blog/jmultiselect2side.html (Demo2) but i don't know how i can retrieve my data when i click submit button..?

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  • Why do I have to explicitly cast sometimes for varargs?

    - by Daniel Lew
    I've got a Class that uses reflection a lot, so I wrote a method to help out: private <T> T callMethod(String methodName, Class[] parameterTypes, Object[] args) { try { Class c = mVar.getClass(); Method m = c.getMethod(methodName, (Class[]) parameterTypes); return (T) m.invoke(mVar, args); } // Insert exception catching here [...] } This worked well for any method that had parameters, however I had to explicitly cast parameterTypes to Class[] in order for this to work for methods with no parameters (e.g., callMethod('funName', null, null);). I've been trying to figure out why this is the case. It seems to me that if parameterTypes, when null, had no concept of what type it is (Class[]), then I'd need to cast it for getMethod(). But if that's the case, why is getMethod() able to tell the difference between null, and (Class[]) null when the method is invoked?

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  • Batch processing JDBC

    - by Wai Hein
    I am practicing JDBC batch processing and having errors: error 1: Unsupported feature error 2: Execute cannot be empty or null Property files include: itemsdao.updateBookName = Update Books set bookname = ? where books.id = ? itemsdao.updateAuthorName = Update books set authorname = ? where books.id = ? I know I can execute about DML statements in one update, but I am practicing batch processing in JDBC. Below is my method public void update(Item item) { String query = null; try { connection = DbConnector.getConnection(); property = SqlPropertiesLoader.getProperties("dml.properties"); connection.setAutoCommit(false); if ( property == null ) { Logging.log.debug("dml.properties does not exist. Check property loader or file name is spelled right"); return; } query = property.getProperty("itemsdao.updateBookName"); statement = connection.prepareStatement(query); statement.setString(1, item.getBookName()); statement.setInt(2, item.getId()); statement.addBatch(query); query = property.getProperty("itemsdao.updateAuthorName"); statement = connection.prepareStatement(query); statement.setString(1, item.getAuthorName()); statement.setInt(2, item.getId()); statement.addBatch(query); statement.executeBatch(); connection.commit(); }catch (ClassNotFoundException e) { Logging.log.error("Connection class does not exist", e); } catch (SQLException e) { Logging.log.error("Violating PK constraint",e); } //helper class th finally { DbUtil.close(connection); DbUtil.closePreparedStatement(statement); }

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  • passing reference of class to another class android error

    - by prolink007
    I recently asked the precursor to this question and had a great reply. However, when i was working this into my android application i am getting an unexpected error and was wondering if everyone could take a look at my code and help me see what i am doing wrong. Link to the initial question: passing reference of class to another class My ERROR: "The constructor ConnectDevice(new View.OnClickListener(){}) is undefined" The above is an error detected by eclipse. Thanks in advance! Below are My code snippets: public class SmartApp extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.intro); final Button connectDeviceButton = (Button) findViewById(R.id.connectDeviceButton); connectDeviceButton.setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { Thread cThread = new Thread(new ConnectDevice(this)); cThread.start(); } }); } } public class ConnectDevice implements Runnable { private boolean connected; private SmartApp smartAppRef; private ObjectInputStream ois; public ConnectDevice(SmartApp smartAppRef) { this.smartAppRef = smartAppRef; } }

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  • Using a custom annotation on a Spring MVC controller method from an interceptor.

    - by Speck
    I have a custom annotation with which I've annotated a method in my Controller alongside a @ReqestMapping. The goal is to use the values set in the custom annotation from a HandlerInterceptor to perform a task. I have the interceptor (HandlerInterceptorAdaptor) mapped and it executes. If I set a breakpoint in my concrete Interceptor I can inspect the HttpServletRequest, HttpServletResponse, and handler Objects. However, I cannot see how to 1, obtain the method which the request is trying to access 2, obtain the Annotations on that method and 3, of course, obtain the values set by the annotation. Can anyone point me to good documentation for this? Please and Thank You.

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  • What does assert do?

    - by peiska
    What does assert do? for example in the function? private static int charAt(String s, int d) { assert d >= 0 && d <= s.length(); if (d == s.length()) return -1; return s.charAt(d); }

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  • Can I write a test without any assert in it ?

    - by stratwine
    Hi, I'd like to know if it is "ok" to write a test without any "assert" in it. So the test would fail only when an exception / error has occured. Eg: like a test which has a simple select query, to ensure that the database configuration is right. So when I change some db-configuration, I re-run this test and check if the configuration is right. ? Thanks!

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  • switch statemt functioning improperly and giving error when i put break;

    - by nav
    The following is the code i used in a program - over here the month variable is an integer switch(month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31; break; case 2: return 28; break; case 4: case 6: case 9: case 11: return 30; break; default: System.out.println("Invalid month."); return 0; } surprisingly, when i use the above switch construct.. it gives an error saying.. code unreachable for statements after each break statement Then i removed all the break statements, and the new code looks like this --- switch(month) { case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31; case 2: return 28; case 4: case 6: case 9: case 11: return 30; default: System.out.println("Invalid month."); return 0; } Now.. after removing the break statements .. the code worked perfectly well.. My question is... in the switch construct.. it is mandatory to use break.. or else the control flow continued.. and all the conditions are tested and executed!! right??? So why in the world is the previous ** syntactically Right** version giving an error.. and the modified syntactically incorrect version running perfectly well.. Any explanation.. anyone!!

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  • How can I get a project type on Netbeans Platform?

    - by Fabio
    Hi folks, Is there a way to know the type of a selected project? I would like to do some specific actions depending of the project type like a J2SE project. Below is the only way that I found to do that: public final class MyAction extends CookieAction { @Override public boolean isEnabled() { if(this.getActivatedNodes() == null || this.getActivatedNodes().length != 1) { return false; } Lookup lookup = this.getActivatedNodes()[0].getLookup(); // gets the selected project Project currentProject = lookup.lookup(Project.class); // checks if the selected project is a J2SE Project or a Maven Project if(currentProject != null && (currentProject.getClass().getSimpleName().equals("J2SEProject") || currentProject.getClass().getSimpleName().equals("NbMavenProjectImpl"))) { return true; } return false; }}

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  • Resizing JPanel to prepare for printing without removing it from its original position

    - by Lesman
    In my program I frequently need to print various JComponents (generally JPanels) and I like them to be full-page. The way I do it now is by using the following code: g2d.scale(pf.getImageableWidth()/componentToPrint.getWidth(), pf.getImageableHeight()/componentToPrint.getHeight()); but this often stretches or otherwise deforms whatever I am trying to print, and I would much prefer to do something that re-sized intelligently, perhaps a functional version of: componentToPrint.setSize(pf.ImageableWidth(), pf.ImageableHeight); or say adding the component into a new JFrame and then setting the frame size (problem is components can't exist in two place at once). I wouldn't care if the resizing would make the rest of the GUI look terrible, as long as it is something that can easily be reset. Is there any way to do this?

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