Search Results

Search found 33603 results on 1345 pages for 'java champion stephen chin'.

Page 804/1345 | < Previous Page | 800 801 802 803 804 805 806 807 808 809 810 811  | Next Page >

  • What can cause my code to run slower when the server JIT is activated?

    - by durandai
    I am doing some optimizations on an MPEG decoder. To ensure my optimizations aren't breaking anything I have a test suite that benchmarks the entire codebase (both optimized and original) as well as verifying that they both produce identical results (basically just feeding a couple of different streams through the decoder and crc32 the outputs). When using the "-server" option with the Sun 1.6.0_18, the test suite runs about 12% slower on the optimized version after warmup (in comparison to the default "-client" setting), while the original codebase gains a good boost running about twice as fast as in client mode. While at first this seemed to be simply a warmup issue to me, I added a loop to repeat the entire test suite multiple times. Then execution times become constant for each pass starting at the 3rd iteration of the test, still the optimized version stays 12% slower than in the client mode. I am also pretty sure its not a garbage collection issue, since the code involves absolutely no object allocations after startup. The code consists mainly of some bit manipulation operations (stream decoding) and lots of basic floating math (generating PCM audio). The only JDK classes involved are ByteArrayInputStream (feeds the stream to the test and excluding disk IO from the tests) and CRC32 (to verify the result). I also observed the same behaviour with Sun JDK 1.7.0_b98 (only that ist 15% instead of 12% there). Oh, and the tests were all done on the same machine (single core) with no other applications running (WinXP). While there is some inevitable variation on the measured execution times (using System.nanoTime btw), the variation between different test runs with the same settings never exceeded 2%, usually less than 1% (after warmup), so I conclude the effect is real and not purely induced by the measuring mechanism/machine. Are there any known coding patterns that perform worse on the server JIT? Failing that, what options are available to "peek" under the hood and observe what the JIT is doing there?

    Read the article

  • How does the event dispatch thread work?

    - by Roman
    With the help of people on stackoverflow I was able to get the following working code of the simples GUI countdown (it just displays a window counting down seconds). My main problem with this code is the invokeLater stuff. As far as I understand the invokeLater send a task to the event dispatching thread (EDT) and then the EDT execute this task whenever it "can" (whatever it means). Is it right? To my understanding the code works like that: In the main method we use invokeLater to show the window (showGUI method). In other words, the code displaying the window will be executed in the EDT. In the main method we also start the counter and the counter (by construction) is executed in another thread (so it is not in the event dispatching thread). Right? The counter is executed in a separate thread and periodically it calls updateGUI. The updateGUI is supposed to update GUI. And GUI is working in the EDT. So, updateGUI should also be executed in the EDT. It is why the code for the updateGUI is inclosed in the invokeLater. Is it right? What is not clear to me is why we call the counter from the EDT. Anyway it is not executed in the EDT. It starts immediately a new thread and the counter is executed there. So, why we cannot call the counter in the main method after the invokeLater block? import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.SwingUtilities; public class CountdownNew { static JLabel label; // Method which defines the appearance of the window. public static void showGUI() { JFrame frame = new JFrame("Simple Countdown"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); label = new JLabel("Some Text"); frame.add(label); frame.pack(); frame.setVisible(true); } // Define a new thread in which the countdown is counting down. public static Thread counter = new Thread() { public void run() { for (int i=10; i>0; i=i-1) { updateGUI(i,label); try {Thread.sleep(1000);} catch(InterruptedException e) {}; } } }; // A method which updates GUI (sets a new value of JLabel). private static void updateGUI(final int i, final JLabel label) { SwingUtilities.invokeLater( new Runnable() { public void run() { label.setText("You have " + i + " seconds."); } } ); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { showGUI(); counter.start(); } }); } }

    Read the article

  • Avoid having a huge collection of ids by calling a DAO.getAll()

    - by Michael Bavin
    Instead of returning a List<Long> of ids when calling PersonDao.getAll() we wanted not to have an entire collection of ids in memory. Seems like returning a org.springframework.jdbc.support.rowset.SqlRowSet and iterate over this rowset would not hold every object in memory. The only problem here is i cannot cast this row to my entity. Is there a better way for this?

    Read the article

  • Question about gets and sets and when to use super classes

    - by Nazgulled
    Hi, I have the following get method: public List<PersonalMessage> getMessagesList() { List<PersonalMessage> newList = new ArrayList<PersonalMessage>(); for(PersonalMessage pMessage : this.listMessages) { newList.add(pMessage.clone()); } return newList; } And you can see that if I need to change the implementation from ArrayList to something else, I can easily do it and I just have to change the initialization of newList and all other code that depends on what getMessageList() returns will still work. Then I have this set method: public void setMessagesList(ArrayList<PersonalMessage> listMessages) { this.listMessages = listMessages; } My question is, should I use List instead of `ArrayList in the method signature? I have decided to use ArrayList because this way I can force the implementation I want, otherwise there could be a mess with different types of lists here and there. But I'm not sure if this is the way to go...

    Read the article

  • How to differentiate between Programmer and JVM Exceptions

    - by Haxed
    As the title suggests, how can I tell a JVM thrown exception from a Programmatically(does this mean, thrown by a programmer or the program) thrown exception ? JVM Exceptions 1) ArrayIndexOutOfBoundsException 2) ClassCastException 3) NullPointerException Programmatically thrown 1) NumberFormatException 2) AssertionError Many Thanks

    Read the article

  • 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?

    Read the article

  • Parsing a String into date with pattern:"dd/MM/yyyy"

    - by kawtousse
    Hi, I want to insert a date having this format MM/dd/YYYY for example:04/29/2010 to 29/04/2010 to be inserted into mysql database in a field typed Date. So i have this code: String dateimput=request.getParameter("datepicker"); DateFormat df = new SimpleDateFormat("dd/MM/yyyy"); Date dt = null; try { dt = df.parse(dateimput); System.out.println("date imput is:" +dt); } catch (ParseException e) { e.printStackTrace(); } but it gives me those error: 1-date imput is:Fri May 04 00:00:00 CEST 2012 (it is not the correct value that have been entered). 2-dismatching with mysql date type. I can not detect the error exactly. Please help.

    Read the article

  • j2ME setLocationListener()

    - by Jeff Catania
    I'm programming a GPS tracking system using the Motorola i335 running on Sprint's IDEN network. I'm using the javax.microedition.location api to find the GPS coordinates. To set up the updating, you use the [setLocationListener][1] method. I originally tried passing (listener,2,1,1). However there was too many invalid locations being received (where the GPS could not get the fix in the specified time), so I changed the parameters to (listener, 20, 20, 1). Now the system barely throws any invalid locations. My goal is to get the fastest number of updates that are realistic. Have any of you found a happy medium for parameters of this method? [1]: http://www-users.cs.umn.edu/~czhou/docs/jsr179/lapi/javax/microedition/location/LocationProvider.html#setLocationListener(javax.microedition.location.LocationListener, int, int, int)

    Read the article

  • Extract Generic types from extended Generic

    - by Brigham
    I'm trying to refactor a class and set of subclasses where the M type does extend anything, even though we know it has to be a subclass of a certain type. That type is parametrized and I would like its parametrized types to be available to subclasses that already have values for M. Is there any way to define this class without having to include the redundant K and V generic types in the parameter list. I'd like to be able to have the compiler infer them from whatever M is mapped to by subclasses. public abstract class NewParametrized<K, V, M extends SomeParametrized<K, V>> { public void someMethodThatTakesKAndV(K k1, V v1) { } } In other words, I'd like the class declaration to look something like: public class NewParametrized<M extends SomeParametrized<K, V>> { And K and V's types would be inferred from the definition of M.

    Read the article

  • Struts 2 Select tag

    - by nathj07
    I'm pretty new to the jsp and struts way of doing things and so far I like what I see. My current question is with the use of the struts select tag. I have a page that displays a number of dropdown boxes using struts select currently the options are hard coded in the jsp. I would like to populate them based on a properties file. However I have no idea where to start. I assume I need to take the contents of a properties file into an Array (of some sort) and assign that to the select tag. My questions are: Where does the code t build the array go? How do I connect that array to the select tag?

    Read the article

  • Deleting orphans with JPA

    - by homaxto
    I have a one-to-one relation where I use CascadeType.PERSIST. This has over time build up a huge amount of child records that has not been deleted, to such an extend that it is reflected in the performance. Now I wish to add some code that cleans up the database removing all the child records that are not referenced by a parent. At the moment we are talking 400K+ records, at I need to run the code on all customer installations just to be sure they do not run into the same problem. I think the best solution would be to run a named query (because we support two databases) that deletes the necessary records, and this is where I get into problems, because how should I write it in JPQL? The result I want can be defined like the following sql statement, which unfortunaltely does not run on MySQL. DELETE FROM child c1 WHERE c1.pk NOT IN (SELECT DISTINCT p.pk FROM child c2 JOIN parent p ON p.child = c2.pk);

    Read the article

  • JPA joined column allow every value...

    - by Fabio Beoni
    I'm testing JPA, in a simple case File/FileVersions tables (Master/Details), with OneToMany relation, I have this problem: in FileVersions table, the field "file_id" (responsable for the relation with File table) accepts every values, not only values from File table. How can I use the JPA mapping to limit the input in FileVersion.file_id only for values existing in File.id? My class are File and FileVersion: FILE CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="FILE_ID") private Long id; @Column(name="NAME", nullable = false, length = 30) private String name; //RELATIONS ------------------------------------------- @OneToMany(mappedBy="file", fetch=FetchType.EAGER) private Collection <FileVersion> fileVersionsList; //----------------------------------------------------- FILEVERSION CLASS @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="VERSION_ID") private Long id; @Column(name="FILENAME", nullable = false, length = 255) private String fileName; @Column(name="NOTES", nullable = false, length = 200) private String notes; //RELATIONS ------------------------------------------- @ManyToOne(fetch=FetchType.EAGER) @JoinColumn(name="FILE_ID", referencedColumnName="FILE_ID", nullable=false) private File file; //----------------------------------------------------- and this is the FILEVERSION TABLE CREATE TABLE `JPA-Support`.`FILEVERSION` ( `VERSION_ID` bigint(20) NOT NULL AUTO_INCREMENT, `FILENAME` varchar(255) NOT NULL, `NOTES` varchar(200) NOT NULL, `FILE_ID` bigint(20) NOT NULL, PRIMARY KEY (`VERSION_ID`), KEY `FK_FILEVERSION_FILE_ID` (`FILE_ID`) ) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1

    Read the article

  • How do I add a library in Eclipse?

    - by jul
    hi, I downloaded the Gson library from http://code.google.com/p/google-gson/. The archive contains the following jar files: google-gson-1.3/gson-1.3-javadoc.jar google-gson-1.3/gson-1.3.jar google-gson-1.3/gson-1.3-sources.jar How do I set my Eclipse to be able to use the package in my projects? Where do I put the documentation? Thanks jul

    Read the article

  • Netbeans Error: "Could not add one or more tag libraries"

    - by JJ4UC
    I am using Netbeans 6.1 and Tomcat 6.0.1.6. I made some very minor changes to a project that had been working and now I am getting the following error: com.sun.rave.web.ui.appbase.ApplicationException: org.apache.jasper.JasperException: Could not add one or more tag libraries. The only change I made was to a backing bean method, no new UI components, jsp, etc. Any direction would be greatly appreciated. Thanks!

    Read the article

  • ArrayList<String> NullPointerException

    - by Carlucho
    Am trying to solve a labyrinth by DFS, using adj List to represent the vertices and edges of the graph. In total there are 12 nodes (3 rows[A,B,C] * 4 cols[0,..,3]). My program starts by saving all the vertex labels (A0,..C3), so far so good, then checks the adjacent nodes, also no problems, if movement is possible, it proceeds to create the edge, here its where al goes wrong. adjList[i].add(vList[j].label); I used the debugger and found that vList[j].label is not null it contains a correct string (ie. "B1"). The only variables which show null are in adjList[i], which leads me to believe i have implemented it wrongly. this is how i did it. public class GraphList { private ArrayList<String>[] adjList; ... public GraphList(int vertexcount) { adjList = (ArrayList<String>[]) new ArrayList[vertexCount]; ... } ... public void addEdge(int i, int j) { adjList[i].add(vList[j].label); //NULLPOINTEREXCEPTION HERE } ... } I will really appreaciate if anyone can point me on the right track regrading to what its going wrong... Thanks!

    Read the article

  • How to add response headers based on Content-type, or getting Content-type before the response is co

    - by Bozho
    I want to set the Expires header for all image/* and text/css. I'm doing this in a Filter. However: before calling chain.doFilter(..) the Content-type is not yet "realized" after calling chain.doFilter(..) the Content-type is set, but so is content-length, which forbids adding new headers (at least in Tomcat implementation) I can use the extensions of the requested resource, but since some of the css files are generated by richfaces by taking them from inside jar-files, the name of the file isn't x.css, but is /xx/yy/zz.xcss/DATB/.... So, is there a way to get the Content-type before the response is committed.

    Read the article

  • Why aren't arrays expandable?

    - by Mustafa
    When we create an array, we cannot change its size; it's fixed. OK, seems nice, we can create a new bigger array and copy the values one by one and that's little slow. What's the technical background of it?

    Read the article

  • CGLIB proxy error after spring bean definition loading into XmlWebApplicationContext at runtime

    - by VasylV
    I load additional singleton beans definitions at runtime from external jar file into existing XmlWebApplicationContext of my application: BeanFactory beanFactory = xmlWebApplicationContext.getBeanFactory(); DefaultListableBeanFactory defaultFactory = (DefaultListableBeanFactory)beanFactory; final URL url = new URL("external.jar"); final URL[] urls = {url}; ClassLoader loader = new URLClassLoader(urls, this.getClass().getClassLoader()); defaultFactory.setBeanClassLoader(loader); final ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(defaultFactory); final DefaultResourceLoader resourceLoader = new DefaultResourceLoader(); resourceLoader.setClassLoader(loader); scanner.setResourceLoader(resourceLoader); scanner.scan("com.*"); Object bean = xmlWebApplicationContext.getBean("externalBean"); After all above xmlWebApplicationContext contains all external definitions of beans. But when i am trying to get bean from context exception is thrown: Couldn't generate CGLIB proxy for class ... I saw in debug mode that in the bean initialization process first time proxy is generated by org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator and than it is tried to generate proxy with org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator but fails with mentioned exception.

    Read the article

  • File Hierarchy system with a web application logic question: List searching

    - by molleman
    I need to search through a list of folders that could have more folders inside it, and add a new folder depending what folder is its parent.(the path is stored as a String for eg = "root/MyCom/home/") Then i fill in a field with a new folder name and add it to the final folder(eg "home/"). Below as you can see , I can navigate to the right location and add the new folder to a current folder, My trouble is that i cannot ensure that currentFolder element is placed back in the list it came from how could i add a folder to a list of folders, that could be within a list of folders,that could be within a list of folders and endless more? YFUser user = (YFUser)getSession().getAttribute(SESSION_USER); Folder newFolder = new Folder(); newFolder.setFolderName(foldername); // this is the path string (root/MyCom/home/) split in the different folder names String folderNames[] = folderLocationString.split("/"); int folderNamesLength = folderNames.length; Folder root = user.getRoot(); Folder currentFolder = root; for(int i=0;i<=folderNamesLength; i++){ // because root is folderNames[i] String folderName = folderNames[i++]; int currentFolderSize = currentFolder.getChildren.getSize(); for(int o=1; o<= currentFolderSize ; o++){ if(currentFolder.getChildren().get(o) instanceof Folder){ if(folderName.equals(currentFolder.getChildren().get(o).getFolderName())){ currentFolder = currentFolder.getChildren().get(o); if (i == counter){ //now i am inside the correct folder and i add it to the list of folders within it //the trouble is knowing how to re add this changed folder back to the list before it currentFolder.getChildren.add(newFolder); } } } } }

    Read the article

< Previous Page | 800 801 802 803 804 805 806 807 808 809 810 811  | Next Page >