Search Results

Search found 33297 results on 1332 pages for 'java java ee'.

Page 835/1332 | < Previous Page | 831 832 833 834 835 836 837 838 839 840 841 842  | Next Page >

  • Primary reasons why programming language runtimes use stacks?

    - by manuel aldana
    Many programming language runtime environments use stacks as their primary storage structure (e.g. see JVM bytecode to runtime example). Quickly recalling I see following advantages: Simple structure (pop/push), trivial to implement Most processors are anyway optimized for stack operations, so it is very fast Less problems with memory fragmentation, it is always about moving memory-pointer up and down for allocation and freeing complete blocks of memory by resetting the pointer to the last entry offset. Is the list complete or did I miss something? Are there programming language runtime environments which are not using stacks for storage at all?

    Read the article

  • Add a listener inside or outside get method

    - by James P.
    I'm learning Swing and have composed an interface using a series of get methods to add components. Is it a good practise to add a Listener inside a get method as follows? I'd like to make things as decoupled as possible. private JButton getConnectButton() { if (connectButton == null) { connectButton = new JButton(); connectButton.setText("Connect"); connectButton.setSize(new Dimension(81, 16)); connectButton.setLocation(new Point(410, 5)); connectButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { // actionPerformed code goes here } }); } return connectButton; }

    Read the article

  • Method with throws Exception: Where is it actually handled?

    - by Esq
    Here is an example code, I am throwing an exception here, it works perfectly fine without the try/catch block of code for some reason. Do I have to handle this inside this method "EntryDelete" or Do I have to handle this where the method is called from? If so can I see an example, what do I have to import in there? What is the acceptable syntax or method to do this? public boolean EntryDelete(int entryId) throws SQLException{ this.open(); kDatabase.delete(kENTRY_TABLE, kENTRY_ENTRY_ID + "=" + entryId, null); this.close(); return true; } Thanks

    Read the article

  • Android Admob is not Showing Up

    - by Brandon
    Admob is not showing up on my emulator or on the device it self. I tried with testing mode on and off. Relevant Manifest data: permissions: <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" /> meta data: <meta-data android:value="true" android:name="AD_REQUEST" /> The x's are actually my ID. My whole main.xml: <com.admob.android.ads.AdView android:id="@+id/ad" android:layout_width="fill_parent" android:layout_height="wrap_content" android:visibility="visible" android:layout_alignParentTop="true"/> Hopefully I can get this solved soon...

    Read the article

  • Problem with 2 levels of inheritance in hibernate mapping

    - by Seth
    Here's my class structure: class A class B extends A class C extends A class D extends C class E extends C And here are my mappings (class bodies omitted for brevity): Class A: @Entity @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @MappedSuperclass @DiscriminatorColumn( name="className", discriminatorType=DiscriminatorType.STRING ) @ForceDiscriminator public abstract class A Class B: @Entity @DiscriminatorValue("B") public class B extends A Class C: @Entity @DiscriminatorValue("C") @MappedSuperclass @DiscriminatorColumn( name="cType", discriminatorType=DiscriminatorType.STRING ) @ForceDiscriminator public abstract class C extends A Class D: @Entity @DiscriminatorValue("D") public class D extends C Class E: @Entity @DiscriminatorValue("E") public class E extends C I've got a class F that contains a set of A: @Entity public class F { ... @OneToMany(fetch=FetchType.LAZY, cascade=CascadeType.ALL) @JoinTable( name="F_A", joinColumns = @JoinColumn(name="A_ID"), inverseJoinColumns = @JoinColumn(name="F_ID") ) private Set<A> aSet = new HashSet<A>(); ... The problem is that whenever I add a new E instance to aSet and then call session.saveOrUpdate(fInstance), hibernate saves with "A" as the discrimiator string. When I try to access the aSet in the F instance, I get the following exception (full stacktrace ommitted for brevity): org.hibernate.InstantiationException: Cannot instantiate abstract class or interface: path.to.class.A Am I mapping the classes incorrectly? How am I supposed to map multiple levels of inheritance? Thanks for the help!

    Read the article

  • Jetty: Stopping programatically causes "1 threads could not be stopped"

    - by Ondra Žižka
    Hi, I have an embedded Jetty 6.1.26 instance. I want to shut it down by HTTP GET sent to /shutdown. So I created a JettyShutdownServlet: @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { resp.setStatus(202, "Shutting down."); resp.setContentType("text/plain"); ServletOutputStream os = resp.getOutputStream(); os.println("Shutting down."); os.close(); resp.flushBuffer(); // Stop the server. try { log.info("Shutting down the server..."); server.stop(); } catch (Exception ex) { log.error("Error when stopping Jetty server: "+ex.getMessage(), ex); } However, when I send the request, Jetty does not stop - a thread keeps hanging in org.mortbay.thread.QueuedThreadPool on the line with this.wait(): // We are idle // wait for a dispatched job synchronized (this) { if (_job==null) this.wait(getMaxIdleTimeMs()); job=_job; _job=null; } ... 2011-01-10 20:14:20,375 INFO org.mortbay.log jetty-6.1.26 2011-01-10 20:14:34,756 INFO org.mortbay.log Started [email protected]:17283 2011-01-10 20:25:40,006 INFO org.jboss.qa.mavenhoe.MavenHoeApp Shutting down the server... 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown [email protected]:17283 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown org.mortbay.jetty.servlet.Context@1672bbb{/,null} 2011-01-10 20:25:40,006 INFO org.mortbay.log Graceful shutdown org.mortbay.jetty.webapp.WebAppContext@18d30fb{/jsp,file:/home/ondra/work/Mavenhoe/trunk/target/classes/org/jboss/qa/mavenhoe/web/jsp} 2011-01-10 20:25:43,007 INFO org.mortbay.log Stopped [email protected]:17283 2011-01-10 20:25:43,009 WARN org.mortbay.log 1 threads could not be stopped 2011-01-10 20:26:43,010 INFO org.mortbay.log Shutdown hook executing 2011-01-10 20:26:43,011 INFO org.mortbay.log Shutdown hook complete It blocks for exactly one minute, then shuts down. I've added the Graceful shutdown, which should allow me to shut the server down from a servlet; However, it does not work as you can see from the log. I've solved it this way: Server server = new Server( PORT ); server.setGracefulShutdown( 3000 ); server.setStopAtShutdown(true); ... server.start(); if( server.getThreadPool() instanceof QueuedThreadPool ){ ((QueuedThreadPool) server.getThreadPool()).setMaxIdleTimeMs( 2000 ); } setMaxIdleTimeMs() needs to be called after the start(), becase the threadPool is created in start(). However, the threads are already created and waiting, so it only applies after all threads are used at least once. I don't know what else to do except some awfulness like interrupting all threads or System.exit(). Any ideas? Is there a good way? Thanks, Ondra

    Read the article

  • Redirecting the response from a filter throws an IllegalStateException

    - by Ritesh M Nayak
    I am writing a filter that will handle all authentication related tasks. My filter is a standard servlet filter as shown below @Override public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { UserSession attribute = (UserSession)request.getSession().getAttribute("user_session_key"); if(attribute!=null && attribute.isValid()) { //proceed as usual, chain.doFilter(req, res); return; } else { //means the user is not authenticated, so we must redirect him/her to the login page ((HttpServletResponse)res).sendRedirect("loginpage"); return; } } But when I do this, I get an IllegalStateException thrown by Tomcat's ResponseFacade. How do I acheive this in a filter. I read in other SO threads that in TOmcat this is a problem as the response object is already commited. How do I get past this ?

    Read the article

  • Finding duplicates in a list using recursion?

    - by user1760892
    I'm suppose to find if there is duplicates in a list and return true or false using recursion only (no loops). So if ArrayList of char is used, [a,b,c,d,e] should return false. [a,a,b,c,d] or [a,b,b,c,c,d] should return true. I've tried and tested different ways and it worked for some cases but not all. I changed my code around and this is what I have now. (Has problem at the last if statement) Can anyone give me some hints? Thanks. public static <T> boolean duplicate(List<T> list) throws NullPointerException { return duplicateHelper(list, list.get(0)); } public static <T> boolean duplicateHelper(List<T> list, T t){ if (list == null) throw new NullPointerException(); if(list.isEmpty()) return false; if(list.size() > 1){ if(t.equals(list.get(1))) return true; } if(list.size() == 1) return false; if(!duplicateHelper(list.subList(1,list.size()), t)){ return duplicate(list.subList(1,list.size())); } return false; }

    Read the article

  • How to use an IN clause in iBATIS?

    - by furtelwart
    I'm using iBATIS to create select statements. Now I would like to implement the following SQL statement with iBATIS: SELECT * FROM table WHERE col1 IN ('value1', 'value2'); With the following approach, the statement is not prepared correctly and no result returns: SELECT * FROM table WHERE col1 IN #listOfValues#; iBATIS seems to restructure this list and tries to interpret it as a string. How can I use the IN clause correctly?

    Read the article

  • Can you return an array from a JAX-WS @WebMethod?

    - by LES2
    I'm pretty sure you can, but in addition to answering the question in the title, could you also explain the pros, cons, caveats, if any, to doing so? I know that you can't return a List, Set, Collection, Map, or any interface, from a WebMethod (which is stupid, IMO, but I don't know what the design reasons were should I should probably withhold judgment). Thanks for any advice. -- LES

    Read the article

  • How to keep the popup menu of a JComboBox open on populating it ?

    - by Stormshadow
    I have a JComboBox on my Panel. One of the popup menu items is 'More' and when I click that I fetch more menu items and add them to the existing list. After this, I wish to keep the popup menu open so that the user realizes that more items have been fetched however, the popup closes. The event handler code I am using is as follows public void actionPerformed(ActionEvent e) { if (e.getSource() == myCombo) { JComboBox selectedBox = (JComboBox) e.getSource(); String item = (String) selectedBox.getSelectedItem(); if (item.toLowerCase().equals("more")) { fetchItems(selectedBox); } selectedBox.showPopup(); selectedBox.setPopupVisible(true); } } private void fetchItems(JComboBox box) { box.removeAllItems(); /* code to fetch items and store them in the Set<String> items */ for (String s : items) { box.addItem(s); } } I do not understand why the showPopup() and setPopupVisible() methods are not functioning as expected.

    Read the article

  • how to call service inside service layer

    - by cometta
    in my service layer public class MyServiceLayerImpl{ @Autowired MyServiceInterface MyServiceLayer } if i have method inside service layer that need to call another service inside service layer. i cannot use this._method ,because, i'm using AOP for caching. In order for the caching to work, i have to use @Autowired to get the service. Therefore, is the above style ok?

    Read the article

  • add Component to JPanel

    - by jouzef19
    Hi , I am using netBeans editor to create desktop application . and i want to add Component without using drag and drop way. I am trying code like this for adding JList to JPanel but nothing showed JList jl = new JList(); Vector<String> v= new Vector<String>(); v.add("one"); v.add("Two"); v.add("Three"); jl.setListData(v); JScrollPane js = new JScrollPane(jl); js.setLocation(50, 50); js.setSize(100, 100); js.setVisible(true); jPanel1.add(js);

    Read the article

  • Scanner cuts off my String after about 2400 characters

    - by Ventrue
    I've got some very basic code like while (scan.hasNextLine()) { String temp = scan.nextLine(); System.out.println(temp); } where scan is a Scanner over a file. However, on one particular line, which is about 6k chars long, temp cuts out after something like 2470 characters. There's nothing special about when it cuts out; it's in the middle of the word "Australia." If I delete characters from the line, the place where it cuts out changes; e.g. if I delete characters 0-100 in the file then Scanner will get what was previously 100-2570. I've used Scanner for larger strings before. Any idea what could be going wrong?

    Read the article

  • JList with custom renderer

    - by AhmadAssaf
    Hello, I have a JList that shows multiple JPanels on them , i have created a custom renderer that returns a new JPanel. The JPanels are displayed in the JList but they are not accessible, i cant select them and if i have a button or a text area in it i can not press it. I want to try if this works in a JList because i want to do further pagination. I managed to get it work by adding panels to a Jscroll pane, but would love to make the JList thing work. Thanks

    Read the article

  • Use my own authentication in tomcat

    - by mabuzer
    how can I force tomcat to use my own implementation of Authenticator, and not the existing one like [FORM, BASIC, DIGEST,, etc]. I know if I added my authentication class name in org.apache.catalina.startup.Authenticators.properties it would work,,, any help please... I need an alternative for this...

    Read the article

  • How to set default values to all wrong or null parameters of method?

    - by Roman
    At the moment I have this code (and I don't like it): private RenderedImage private RenderedImage getChartImage (GanttChartModel model, String title, Integer width, Integer height, String xAxisLabel, String yAxisLabel, Boolean showLegend) { if (title == null) { title = ""; } if (xAxisLabel == null) { xAxisLabel = ""; } if (yAxisLabel == null) { yAxisLabel = ""; } if (showLegend == null) { showLegend = true; } if (width == null) { width = DEFAULT_WIDTH; } if (height == null) { height = DEFAULT_HEIGHT; } ... } How can I improve it? I have some thoughts about introducing an object which will contain all these parameters as fields and then, maybe, it'll be possible to apply builder pattern. But still don't have clear vision how to implement that and I'm not sure that it's worth to be done. Any other ideas?

    Read the article

  • JavaME FileConnection url

    - by Trimack
    Hi there, I want to save data to my Sony Ericsson K750i. I know the phone implements FileConnection version 1.0. The list of roots taken from FileSystemRegistry.listRoots(); returns single element named "c:/". I want to save a file.txt just about anywhere, but preferably to the memory stick attached. Unfortunately, it doesn't seem to work. It throws an IOException without any message. I tried opening the fileconnection on numerous roots like c:/, C:/, /, ./, root1/, SDCard/, CFCard/, MemoryStick/ and perhaps some more but without any luck. The exception is thrown right after this line for any of those roots: FileConnection filecon = (FileConnection) Connector.open("file:///MemoryStick/file.txt"); Please, what URL should i use?

    Read the article

  • hibernate versioning parent entity

    - by Priit
    Consider two entities Parent and Child. Child is part of Parent's transient collection Child has a ManyToOne mapping to parent with FetchType.LAZY Both are displayed on the same form to a user. When user saves the data we first update Parent instance and then Child collection (both using merge). Now comes the tricky part. When user modifies only Child property on the form then hibernate dirty checking does not update Parent instance and thus does not increase optimistic locking version number for that entity. I would like to see situation where only Parent is versioned and every time I call merge for Parent then version is always updated even if actual update is not executed in db.

    Read the article

< Previous Page | 831 832 833 834 835 836 837 838 839 840 841 842  | Next Page >