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  • Java method overloading + double dispatch

    - by Max
    Can anybody explain in detail the reason the overloaded method print(Parent parent) is invoked when working with Child instance in my test piece of code? Any pecularities of virtual methods or methods overloading/resolution in Java involved here? Any direct reference to Java Lang Spec? Which term describes this behaviour? Thanks a lot. public class InheritancePlay { public static class Parent { public void doJob(Worker worker) { System.out.println("this is " + this.getClass().getName()); worker.print(this); } } public static class Child extends Parent { } public static class Worker { public void print(Parent parent) { System.out.println("Why this method resolution happens?"); } public void print(Child child) { System.out.println("This is not called"); } } public static void main(String[] args) { Child child = new Child(); Worker worker = new Worker(); child.doJob(worker); } }

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  • can't persist jpa entity in app engine

    - by Bunny Rabbit
    public class Blobx { private String name; private BlobKey blobKey; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Key id; //getters and setters } public class Userx { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Key id; private String name; @OneToMany private List<Blobx> blobs; //getters and setters } while persiting the above Userx entity object i am encountering java.lang.IllegalStateException: Field "entities.Userx.blobs" contains a persistable object that isnt persistent, but the field doesnt allow cascade-persist!

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  • Classes missing if application runs for a long time

    - by Rogach
    I have a funny problem - if my application runs for a long time ( 20h), then sometimes I get NoClassDefFound error - seems like JVM decided that the class is not going to be used anyway and GCd it. To be a bit more specific, here's an example case: object ErrorHandler extends PartialFunction[Throwable,Unit] { def isDefinedAt(t: Throwable) = true def apply(e: Throwable) =e match { // ... handle errors } } // somewhere else in the code... try { // ... long running code, can take more than 20 hours to complete } catch (ErrorHandler) And I get the following exception: Exception in thread "main" java.lang.NoClassDefFoundError: org/rogach/avalanche/ErrorHandler$ If that try/catch block runs for smaller amounts of time, everything works as expected. If anyone is interested, here is the codebase in question: Avalanche I need to note that I saw this and similar problems only on Cent OS 5 machines, using JRE 6u26 and Scala 2.9.1 / 2.9.2. What could be the cause of this problem?

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  • Making php-mode Compatible with Emacs 23

    - by Kristopher Johnson
    I am using Emacs 23 and php-mode.el 1.5.0. When I have this in my .emacs: (require 'php-mode) I get this error message when Emacs starts: Warning (initialization): An error occurred while loading `/Users/kdj/.emacs': error: `c-lang-defconst' must be used in a file To ensure normal operation, you should investigate and remove the cause of the error in your initialization file. Start Emacs with the `--debug-init' option to view a complete error backtrace. If I evaluate (require 'php-mode) after Emacs starts, I don't get any error messages. I found a blog entry which indicates that this problem is specific to Emacs 23 (that is, there is no error with Emacs 22.x), but it doesn't give any solutions. Don't know if this matters, but I'm using Mac OS X, and I built Emacs from the current CVS sources, using ./configure --with-ns. Anybody know what's going on here, and/or how I can fix it?

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  • Calling Python from Java through scripting engine (jython)?

    - by griffin
    I'm trying to call Jython from a Java 6 application using javax.script: import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; import javax.script.ScriptException; public class jythonEx { public static void main (String args[]) throws ScriptException { ScriptEngineManager mgr = new ScriptEngineManager(); ScriptEngine pyEngine = mgr.getEngineByName("python"); try { pyEngine.eval("print \"Python - Hello, world!\""); } catch (Exception ex) { ex.printStackTrace(); } } } This is causing a NullPointerException: java.lang.NullPointerException at jythonEx.main(jythonEx.java:12) Does anyone have any idea what I'm doing wrong here? Edit: Thanks for the responses! I added jython.jar to the classpath and it runs properly: java -cp "./;jython.jar" jythonEx

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  • i18n Spring MVC

    - by Enrique
    Hello. I want to use SessionLocaleResolver to get the locale from user session. The documentation says this: "Another option of resolving locales is by SessionLocaleResolver. It resolves locales by inspecting a predefined attribute in a user’s session. If the session attribute doesn’t exist, this locale resolver will determine the default locale from the accept-language HTTP header." But it does not say which attribute do I have to put in session. Y tried saving in session an attribute "lang" with value "en" but it did not work. Anybody knows which attribute do I have to save in session (key,value)?

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  • Eclipse launch error when trying to run an Android app.

    - by user259642
    I'm trying to set up my workstation for Android development with Eclipse Galileo. I installed the latest ADT plugin and the Android SDK, but I get this error when I try to run any basic Android project I create. eclipse.buildId=M20090917-0800 java.version=1.6.0_17 java.vendor=Sun Microsystems Inc. BootLoader constants: OS=win32, ARCH=x86, WS=win32, NL=en_US Framework arguments: -product org.eclipse.epp.package.java.product -product org.eclipse.epp.package.java.product Command-line arguments: -os win32 -ws win32 -arch x86 -product org.eclipse.epp.package.java.product -data C:\Documents and Settings\dmcnamar\workspace -product org.eclipse.epp.package.java.product Error Tue Jan 26 18:00:41 EST 2010 An internal error occurred during: "Launching HelloWorld". java.lang.NullPointerException at com.android.ide.eclipse.adt.internal.launch.AndroidLaunchController.launch(Unknown Source) at com.android.ide.eclipse.adt.internal.launch.LaunchConfigDelegate.doLaunch(Unknown Source) at com.android.ide.eclipse.adt.internal.launch.LaunchConfigDelegate.launch(Unknown Source) at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:853) at org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.java:703) at org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:866) at org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1069) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

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  • android: customized text selector

    - by Yang
    I wanted to design a customized text selector that changed the text color when user clicks the TextView. But got the following error: java.lang.RuntimeException: Unable to start activity ComponentInfo{}: android.view.InflateException: Binary XML file line #55: Error inflating class here is what I have: res/text_selector.xml <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_enabled="false" android:state_focused="true" android:drawable="@color/black" /> <item android:state_pressed="true" android:drawable="@color/blue" /> <item android:state_focused="true" android:drawable="@color/black" /> </selector> layout/textview.xml <TextView android:id = "@+id/last_page_button" android:text="@string/last_page_button_string" android:gravity="center_horizontal" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#ffffff" android:textColor = "@drawable/text_selector" android:layout_weight="1" /> values/color.xml <resources> <color name="white">#ffffffff</color> <color name="black">#ff000000</color> <color name="blue">#ffccddff</color>

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  • How to get entries from the second level query cache ?

    - by fabien7474
    In my grails application, I want to display all the current entries of the second-level cache from all regions. My code is as following : def getCacheStats() { StatisticsImpl stats = sessionFactory.statistics for (regionName in stats.secondLevelCacheRegionNames) { log.debug stats.getSecondLevelCacheStatistics(regionName).entries } } However everything works fine as long as the region name is not org.hibernate.cache.StandardQueryCache (region used for Query Cache). In that case, an exception is thrown : java.lang.ClassCastException: org.hibernate.cache.QueryKey cannot be cast to org.hibernate.cache.CacheKey Having googling around, I didn't find any clues about how to display the list of entries of the cached query result sets associated with regions StandardQueryCache and UpdateTimestampsCache. Could you please help me find a solution for this?

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  • Unbelievable: Cannot cast from class X to its super class

    - by Phuong Nguyen de ManCity fan
    I'm encountering a very weird problem with Spring (3.0.1.RELEASE), TestNG (5.11) and Maven Surefire (2.5). I have a test class that extends a Spring helper class for testNG so that test context can be loaded from an xml file (that contains some bean definitions). My project was imported into eclipse using m2eclipse (using Import Maven Project) The class run fine in Eclipse TestNG runner. However, it throws this exception with Maven Surefire Caused by: java.lang.ClassCastException: com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl cannot be cast to javax.xml.parsers.DocumentBuilderFactory at javax.xml.parsers.DocumentBuilderFactory.newInstance(DocumentBuilderFactory.java:123) at org.springframework.beans.factory.xml.DefaultDocumentLoader.createDocumentBuilderFactory(DefaultDocumentLoader.java:89) at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:70) at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:388) I have eliminated all involved dependencies in my pom so that the two classes com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl and javax.xml.parsers.DocumentBuilderFactory are coming from JRE only (the rt.jar). So, it looks so unbelievable to me. I wonder if there is any mechanism in loading class that can explain for this behavior? Thanks.

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  • Ubuntu: SWT App Can't Load GTK Library

    - by Nifty255
    I have supplied the Linux SWT jar and packaged my app in Eclipse to include swt.jar inside my app's jar. When I try to run it on Ubuntu, I get the following error text (posting only cause): Caused by: java.lang.UnsatisfiedLinkError: Could not load SWT library. Reasons: no swt-pi-gtk-4234 in java.library.path no swt-pi-gtk in java.library.path /home/nifty/.swt/lib/linux/x86/libswt-pi-gtk-4234.so: libgtk-x11-2.0.so.0: cannot open shared object file: No such file or directory Can't load library: /home/nifty/.swt/lib/linux/x86/libswt-pi-gtk.so This indicates to me it can't load a GTK file, but anything beyond that, and I'm at a loss. I'm only using Ubuntu to test my app, so I know very little.

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  • Java 'Prototype' pattern - new vs clone vs class.newInstance

    - by Guillaume
    In my project there are some 'Prototype' factories that create instances by cloning a final private instance. The author of those factories says that this pattern provides better performance than calling 'new' operator. Using google to get some clues about that, I've found nothing really relevant about that. Here is a small excerpt found in a javdoc from an unknown project javdoc from an unknown project Sadly, clone() is rather slower than calling new. However it is a lot faster than calling java.lang.Class.newInstance(), and somewhat faster than rolling our own "cloner" method. For me it's looking like an old best practice of the java 1.1 time. Does someone know more about this ? Is this a good practice to use that with 'modern' jvm ?

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  • Huge file in Clojure and Java heap space error

    - by trzewiczek
    I posted before on a huge XML file - it's a 287GB XML with Wikipedia dump I want ot put into CSV file (revisions authors and timestamps). I managed to do that till some point. Before I got the StackOverflow Error, but now after solving the first problem I get: java.lang.OutOfMemoryError: Java heap space error. My code (partly taken from Justin Kramer answer) looks like that: (defn process-pages [page] (let [title (article-title page) revisions (filter #(= :revision (:tag %)) (:content page))] (for [revision revisions] (let [user (revision-user revision) time (revision-timestamp revision)] (spit "files/data.csv" (str "\"" time "\";\"" user "\";\"" title "\"\n" ) :append true))))) (defn open-file [file-name] (let [rdr (BufferedReader. (FileReader. file-name))] (->> (:content (data.xml/parse rdr :coalescing false)) (filter #(= :page (:tag %))) (map process-pages)))) I don't show article-title, revision-user and revision-title functions, because they just simply take data from a specific place in the page or revision hash. Anyone could help me with this - I'm really new in Clojure and don't get the problem.

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  • ASP.NET MVC AJAX value not displaying

    - by mazhar kaunain baig
    View: function success(arg) { var obj = arg.get_response().get_object(); if (obj.ErrorMessage === '') { var answer = document.createElement('div'); answer.appendChild(document.createTextNode(obj.Answer)); document.getElementById('answers').appendChild(answer); } else { document.getElementById('errors').innerHTML = obj.ErrorMessage; } } <% using (Ajax.BeginForm("EditOrganizationMeta", "Organization", new AjaxOptions { HttpMethod = "POST", OnSuccess = "success" })) { %> <input type="submit" name="button<%=OrganizationMeta.vcr_MetaKey + Lang.int_LangId %>" value="Save" /> <div id="errors"></div> <div id="answers"></div> <% } %> Controller: [HttpPost] [ValidateInput(false)] public ActionResult EditOrganizationMeta(FormCollection collection) { return Json(new { Answer = "Record Successfully Saved", ErrorMessages = "Title is required" }); } The thing is that success method in the javascript is not getting the required parameters. It is printing undefined there. Is there a problem in javascript method OnSuccess?

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  • Groovy 1.7 changes "final"?

    - by Aaron L. Carlow
    Just started learning Groovy, got the PragProg book "Programming Groovy" and had a problem compiling one of the sample scripts: class GCar2 { final miles = 0 def getMiles() { println "getMiles called" miles } def drive(dist) { if (dist > 0) { miles += dist } } } def car = new GCar2() println "Miles: $car.miles" println 'Driving' car.drive(10) println "Miles: $car.miles" try { print 'Can I see the miles? ' car.miles = 12 } catch (groovy.lang.ReadOnlyPropertyException ex) { println ex.message GroovyCar2.groovy: 20: cannnot access final field or property outside of constructor. @ line 20, column 35. def drive(dist) { if (dist > 0) miles += dist } ^ Groovy versions prior to 1.7 do not give an error. I looked through whatever documentation I could find and did not see the issue discussed. What is going on here? Aaron

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  • Identify cause of hundreds of AJP threads in Tomcat

    - by Rich
    We have two Tomcat 6.0.20 servers fronted by Apache, with communication between the two using AJP. Tomcat in turn consumes web services on a JBoss cluster. This morning, one of the Tomcat machines was using 100% of CPU on 6 of the 8 cores on our machine. We took a heap dump using JConsole, and then tried to connect JVisualVM to get a profile to see what was taking all the CPU, but this caused Tomcat to crash. At least we had the heap dump! I have loaded the heap dump into Eclipse MAT, where I have found that we have 565 instances of java.lang.Thread. Some of these, obviously, are entirely legitimate, but the vast majority are named "ajp-6009-XXX" where XXX is a number. I know my way around Eclipse MAT pretty well, but haven't been able to find an explanation for it. If anyone has some pointers as to why Tomcat may be doing this, or some hints on finding out why using Eclipse MAT, that'd be appreciated!

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  • How to make a loop over all keys of a HashMap?

    - by Roman
    I try to do it in the following way: public String getValue(String service, String parameter) { String inputKey = service + ":" + parameter; Set keys = name2value.keySet(); Iterator itr = keys.iterator(); while (itr.hasNext()) { if (inputKey.equal(itr.next())) { return name2value.get(inputKey); } return ""; } } And I get an error message: cannot find symbol method.equal(java.lang.Object). I think it is because itr.next() is not considered as a string. How can I solve this problem? I tried to replace Set keys by Set<String> keys. It did not help.

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  • Classloader problems Tomcat 6 javagent

    - by alecswan
    I am using Salve Dependency Injection library that instruments the byte code of the web application. I specified -javaagent in Tomcat VM options and pointed it to the Salve agent jar. The agent jar gets loaded, but then it throws a java.lang.NoClassDefFoundError unable to find classes that are in other Salve jars which are located in WEB-INF/lib folder of my web app. I can solve this problem by putting those JARs in Tomcat/endorsed folder. However, some of those jars depend on third-party libraries, such as Spring and servlet-api.jar. Therefore, I am forced to put all these dependencies in Tomcat/endorsed as well. Could anybody suggest a better way for handling dependencies of a Tomcat javaagent? Thanks.

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  • groovy (java) error grabbing files

    - by senzacionale
    i can not grab files. I get: java.lang.RuntimeException: Error grabbing Grapes -- [unresolved dependency: org.apache.ivy#ivy;2.1.0: not found start of script which grab files import groovy.text.SimpleTemplateEngine import java.security.MessageDigest import org.apache.commons.cli.OptionBuilder import org.apache.commons.cli.Options import org.apache.commons.cli.PosixParser import org.apache.commons.io.FileUtils import org.apache.ivy.core.settings.IvySettings import org.apache.ivy.plugins.parser.m2.PomModuleDescriptorParser import org.apache.tools.ant.Project import org.apache.tools.ant.ProjectHelper import org.apache.tools.ant.types.Path import org.apache.commons.cli.HelpFormatter //First grab the grapes we need for the script and create a few beans to hold some values @Grab(group = 'org.apache.ant', module = 'ant', version = '1.7.1') @Grab(group = 'commons-io', module = 'commons-io', version = '1.4') @Grab(group = 'commons-cli', module = 'commons-cli', version = '1.2') @Grab(group = 'org.apache.ivy', module = 'ivy', version = '2.1.0')

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  • to escape or not to escape: well formed XHTML with diacritics

    - by andresmh
    Say that you have a XHTML document in English but it has accented characters (e.g. meta name="author" content="José"). Let's say you have no control over the HTTP headers. Should the characters be replaced for their corresponding named entities (e.g. &aacute;, etc)? Should the doc type and the xml:lang attribute be set to English? I know I can check the W3C recommendation but I am asking more from a practical point of view.

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  • Clojure / HBase: How to Import HBaseTestingUtility in v0.94.6.1

    - by David Williams
    In Clojure, if I want to start a test cluster using the hbase testing utility, I have to annotate my dependencies with: [org.apache.hbase/hbase "0.92.2" :classifier "tests" :scope "test"] First of all, I have no idea what this means. According to leiningens sample project.clj ;; Dependencies are listed as [group-id/name version]; in addition ;; to keywords supported by Pomegranate, you can use :native-prefix ;; to specify a prefix. This prefix is used to extract natives in ;; jars that don't adhere to the default "<os>/<arch>/" layout that ;; Leiningen expects. Question 1: What does that mean? Question 2: If I upgrade the version: [org.apache.hbase/hbase "0.94.6.1" :classifier "tests" :scope "test"] Then I receive a ClassNotFoundException Exception in thread "main" java.lang.ClassNotFoundException: org.apache.hadoop.hbase.HBaseConfiguration Whats going on here and how do I fix it?

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  • [Android] ProgressBar inside SimpleAdapter

    - by lemon
    I'm trying to add a ProgressBar to my row.xml view but I can't seem to make it work I keep getting 06-09 12:44:44.802: ERROR/AndroidRuntime(1012): java.lang.IllegalStateException: android.widget.ProgressBar is not a view that can be bounds by this SimpleAdapter ArrayList arr = new ArrayList(); HashMap map = new HashMap(); map.put("progress", 10); arr.add(map); String [] fieldNames = {"progress"}; int [] fieldIds = {R.id.progress}; SimpleAdapter adapter = new SimpleAdapter(this, arr, R.layout.row, fieldNames, fieldIds); list = (ListView) findViewById(R.id.list); list.setAdapter(adapter); <ProgressBar android:id="@+id/progress" style="?android:attr/progressBarStyleHorizontal" android:max="100" android:progress="5" android:layout_width="fill_parent" android:layout_height="fill_parent" /> Does anyone have any idea what I'm missing?

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  • Sliding a div across to left and the next div appears

    - by littleMan
    I have this form Im creating and when you click on the "Next" button I want to slide the next form() across to the left this is my function jQuery('input[name^=Next]').click(function () { current.animate({ marginLeft: -current.width() }, 750); current = current.next(); }); That function isn't working the way I want to. it slides the text in the container across not the whole container it could be a css problem for all I know. And my form which has a class name .wikiform doesn't center horizontally. here is my full code. I'm not that experience in javascript so you would be appreciated. cut and paste and try it out <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" /> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <script type="text/javascript" language="javascript" src="Scripts/jquery-1.4.4.js"></script> <script type="text/javascript" language="javascript" src="Scripts/jquery-easing.1.2.pack.js"></script> <script type="text/javascript" language="javascript"> (function ($) { $.fn.WikiForm = function (options) { this.Mode = options.mode || 'CancelOk' || 'Ok' || 'Wizard'; var current = jQuery('.wikiform .view :first'); function positionForm() { //jQuery('.wikiform').css( {'top': jQuery('body') .css('overflow-y', 'hidden'); jQuery('<div id="overlay"></div>') .insertBefore('.wikiform') .css('top', jQuery(document).scrollTop()) .animate({ 'opacity': '0.8' }, 'slow'); jQuery('.wikiform') .css('height', jQuery('.wikiform .wizard .view:first').height() + jQuery('.wikiform .navigation').height()) .css('top', window.screen.availHeight / 2 - jQuery('.wikiform').height() / 2) .css('width', jQuery('.wikiform .wizard .view:first').width()) .css('left', -jQuery('.wikiform').width()) .animate({ marginLeft: jQuery(document).width() / 2 + jQuery('.wikiform').width() / 2 }, 750); jQuery('.wikiform .wizard') .css('overflow', 'hidden') .css('height', jQuery('.wikiform .wizard .view:first').height() ); } if (this.Mode == "Wizard") { return this.each(function () { var current = jQuery('.wizard .view :first'); var form = jQuery(this); positionForm(); jQuery('input[name^=Next]').click(function () { current.animate({ marginLeft: -current.width() }, 750); current = current.next(); }); jQuery('input[name^=Back]').click(function () { alert("Back"); }); }); } else if (this.Mode == "CancelOk") { return this.each(function () { }); } else { return this.each(function () { }); } }; })(jQuery); $(document).ready(function () { jQuery(window).bind("load", function () { jQuery(".wikiform").WikiForm({ mode: 'Wizard', speed:750, ease:"expoinout" }); }); }); </script> <style type="text/css"> body { margin:0px; } #overlay { background-color:Black; position:absolute; top:0; left:0; height:100%; width:100%; } .wikiform { background-color:Green; position:absolute; } .wikiform .wizard { clear: both; } .wizard { position: relative; left: 0; top: 0; width: 100%; list-style-type: none; } .wizard .view { float:left; } .view .form { } .navigation { float:right; clear:left } #view1 { background-color:Aqua; width:300px; height:300px; } #view2 { background-color:Fuchsia; width:300px; height:300px; } </style> <title></title> </head> <body><form action="" method=""><div id="layout"> <div id="header"> Header </div> <div id="content" style="height:2000px"> Content </div> <div id="footer"> Footer </div> </div> <div id="formView1" class="wikiform"> <div class="wizard"> <div id="view1" class="view"> <div class="form"> Content 1 </div> </div> <div id="view2" class="view"> <div class="form"> Content 2 </div> </div> </div> <div class="navigation"> <input type="button" name="Back" value=" Back " /> <input type="button" name="Next " class="Next" value=" Next " /> <input type="button" name="Cancel" value="Cancel" /> </div> </div></form></body></html>

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  • NullPointerException on facebook login using servlet

    - by khoyendra
    after solve class notfound exeption i have to find error when i login in face book using given example http://code.google.com/p/facebook-java-api/wiki/Examples java.lang.NullPointerException com.google.code.facebookapi.ExtensibleClient.<init>(ExtensibleClient.java:111) com.google.code.facebookapi.ExtensibleClient.<init>(ExtensibleClient.java:99) com.google.code.facebookapi.ExtensibleClient.<init>(ExtensibleClient.java:95) com.google.code.facebookapi.FacebookXmlRestClientBase.<init>(FacebookXmlRestClientBase.java:44) com.google.code.facebookapi.FacebookXmlRestClient.<init>(FacebookXmlRestClient.java:10) FaceBookCrawl.FacebookUserFilter.doFilter(FacebookUserFilter.java:107) FaceBookCrawl.FacebookUserFilter.doPost(FacebookUserFilter.java:181) javax.servlet.http.HttpServlet.service(HttpServlet.java:710) javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

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  • Getting a NullPointerException at seemingly random intervals, not sure why

    - by Miles
    I'm running an example from a Kinect library for Processing (http://www.shiffman.net/2010/11/14/kinect-and-processing/) and sometimes get a NullPointerException pointing to this line: int rawDepth = depth[offset]; The depth array is created in this line: int[] depth = kinect.getRawDepth(); I'm not exactly sure what a NullPointerException is, and much googling hasn't really helped. It seems odd to me that the code compiles 70% of the time and returns the error unpredictably. Could the hardware itself be affecting it? Here's the whole example if it helps: // Daniel Shiffman // Kinect Point Cloud example // http://www.shiffman.net // https://github.com/shiffman/libfreenect/tree/master/wrappers/java/processing import org.openkinect.*; import org.openkinect.processing.*; // Kinect Library object Kinect kinect; float a = 0; // Size of kinect image int w = 640; int h = 480; // We'll use a lookup table so that we don't have to repeat the math over and over float[] depthLookUp = new float[2048]; void setup() { size(800,600,P3D); kinect = new Kinect(this); kinect.start(); kinect.enableDepth(true); // We don't need the grayscale image in this example // so this makes it more efficient kinect.processDepthImage(false); // Lookup table for all possible depth values (0 - 2047) for (int i = 0; i < depthLookUp.length; i++) { depthLookUp[i] = rawDepthToMeters(i); } } void draw() { background(0); fill(255); textMode(SCREEN); text("Kinect FR: " + (int)kinect.getDepthFPS() + "\nProcessing FR: " + (int)frameRate,10,16); // Get the raw depth as array of integers int[] depth = kinect.getRawDepth(); // We're just going to calculate and draw every 4th pixel (equivalent of 160x120) int skip = 4; // Translate and rotate translate(width/2,height/2,-50); rotateY(a); for(int x=0; x<w; x+=skip) { for(int y=0; y<h; y+=skip) { int offset = x+y*w; // Convert kinect data to world xyz coordinate int rawDepth = depth[offset]; PVector v = depthToWorld(x,y,rawDepth); stroke(255); pushMatrix(); // Scale up by 200 float factor = 200; translate(v.x*factor,v.y*factor,factor-v.z*factor); // Draw a point point(0,0); popMatrix(); } } // Rotate a += 0.015f; } // These functions come from: http://graphics.stanford.edu/~mdfisher/Kinect.html float rawDepthToMeters(int depthValue) { if (depthValue < 2047) { return (float)(1.0 / ((double)(depthValue) * -0.0030711016 + 3.3309495161)); } return 0.0f; } PVector depthToWorld(int x, int y, int depthValue) { final double fx_d = 1.0 / 5.9421434211923247e+02; final double fy_d = 1.0 / 5.9104053696870778e+02; final double cx_d = 3.3930780975300314e+02; final double cy_d = 2.4273913761751615e+02; PVector result = new PVector(); double depth = depthLookUp[depthValue];//rawDepthToMeters(depthValue); result.x = (float)((x - cx_d) * depth * fx_d); result.y = (float)((y - cy_d) * depth * fy_d); result.z = (float)(depth); return result; } void stop() { kinect.quit(); super.stop(); } And here are the errors: processing.app.debug.RunnerException: NullPointerException at processing.app.Sketch.placeException(Sketch.java:1543) at processing.app.debug.Runner.findException(Runner.java:583) at processing.app.debug.Runner.reportException(Runner.java:558) at processing.app.debug.Runner.exception(Runner.java:498) at processing.app.debug.EventThread.exceptionEvent(EventThread.java:367) at processing.app.debug.EventThread.handleEvent(EventThread.java:255) at processing.app.debug.EventThread.run(EventThread.java:89) Exception in thread "Animation Thread" java.lang.NullPointerException at org.openkinect.processing.Kinect.enableDepth(Kinect.java:70) at PointCloud.setup(PointCloud.java:48) at processing.core.PApplet.handleDraw(PApplet.java:1583) at processing.core.PApplet.run(PApplet.java:1503) at java.lang.Thread.run(Thread.java:637)

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