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  • ExecutorSerrvice 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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  • JAXB doesn't unmarshal list of interfaces

    - by Joker_vD
    It seems JAXB can't read what it writes. Consider the following code: interface IFoo { void jump(); } @XmlRootElement class Bar implements IFoo { @XmlElement public String y; public Bar() { y = ""; } public Bar(String y) { this.y = y; } @Override public void jump() { System.out.println(y); } } @XmlRootElement class Baz implements IFoo { @XmlElement public int x; public Baz() { x = 0; } public Baz(int x) { this.x = x; } @Override public void jump() { System.out.println(x); } } @XmlRootElement public class Holder { private List<IFoo> things; public Holder() { things = new ArrayList<>(); } @XmlElementWrapper @XmlAnyElement public List<IFoo> getThings() { return things; } public void addThing(IFoo thing) { things.add(thing); } } // ... try { JAXBContext context = JAXBContext.newInstance(Holder.class, Bar.class, Baz.class); Holder holder = new Holder(); holder.addThing(new Bar("1")); holder.addThing(new Baz(2)); holder.addThing(new Baz(3)); for (IFoo thing : holder.getThings()) { thing.jump(); } StringWriter s = new StringWriter(); context.createMarshaller().marshal(holder, s); String data = s.toString(); System.out.println(data); StringReader t = new StringReader(data); Holder holder2 = (Holder)context.createUnmarshaller().unmarshal(t); for (IFoo thing : holder2.getThings()) { thing.jump(); } } catch (Exception e) { System.err.println(e.getMessage()); } It's a simplified example, of course. The point is that I have to store two very differently implemented classes, Bar and Baz, in one collection. Well, I observed that they have pretty similar public interface, so I created an interface IFoo and made them two to implement it. Now, I want to have tools to save and load this collection to/from XML. Unfortunately, this code doesn't quite work: the collection is saved, but then it cannot be loaded! The intended output is 1 2 3 some xml 1 2 3 But unfortunately, the actual output is 1 2 3 some xml com.sun.org.apache.xerces.internal.dom.ElementNSImpl cannot be cast to testapplication1.IFoo Apparently, I need to use the annotations in a different way? Or to give up on JAXB and look for something else? I, well, can write "XMLNode toXML()" method for all classes I wan't to (de)marshal, but...

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  • How to retrieve the ordered list of best articles having a minimum number of votes by using HSQL ?

    - by fabien7474
    I have a Vote domain class from my grails application containing properties like article_id and note I want to HQL query the Vote domain class in order to retrieve the 5 best rated articles having at least 10 votes. I tried : SELECT v.article_id, avg(v.note), count(*) FROM vote v where count(*) >= 10 group by v.article_id order by avg(v.note) desc limit 5; But unfortunately the insertion of where count(*) >= 10 throws an error. How can I do that in a simple way? Thank you for your help.

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  • Is this the right way to write a ProtocolDecoder in MINA?

    - by phpscriptcoder
    public class CustomProtocolDecoder extends CumulativeProtocolDecoder{ byte currentCmd = -1; int currentSize = -1; boolean isFirst = false; @Override protected boolean doDecode(IoSession is, ByteBuffer bb, ProtocolDecoderOutput pdo) throws Exception { if(currentCmd == -1) { currentCmd = bb.get(); currentSize = Packet.getSize(currentCmd); isFirst = true; } while(bb.remaining() > 0) { if(!isFirst) { currentCmd = bb.get(); currentSize = Packet.getSize(currentCmd); } else isFirst = false; //System.err.println(currentCmd + " " + bb.remaining() + " " + currentSize); if(bb.remaining() >= currentSize - 1) { Packet p = PacketDecoder.decodePacket(bb, currentCmd); pdo.write(p); } else { bb.flip(); return false; } } if(bb.remaining() == 0) return true; else return false; } } Anyone see anything wrong with this code? When a lot of packets are received at once, even when only one client is connected, one of them might get cut off at the end (12 bytes instead of 15 bytes, for example) which is obviously bad.

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  • Spring MVC: should service layer be returning operation specific DTO's ?

    - by arrages
    In my Spring MVC application I am using DTO in the presentation layer in order to encapsulate the domain model in the service layer. The DTO's are being used as the spring form backing objects. hence my services look something like this: userService.storeUser(NewUserRequestDTO req); The service layer will translate DTO - Domain object and do the rest of the work. Now my problem is that when I want to retrieve a DTO from the service to perform say an Update or Display I can't seem to find a better way to do it then to have multiple methods for the lookup that return different DTO's like... EditUserRequestDTO userService.loadUserForEdit(int id); DisplayUserDTO userService.loadUserForDisplay(int id); but something does not feel right about this approach. The reason do have separate DTO's is that DisplayUserDTO is strongly typed to be read only and also there are many properties of user that are entities from a lookup table in the db (like city and state) so the DisplayUserDTO would have the string description of the properties while the EditUserRequestDTO will have the id's that will back the select drop down lists in the forms. What do you think? thanks

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  • Revalidate JPanel's parent frame

    - by Tom Brito
    I need show/hide some fields of my panel, and I want the panel to fit the frame. How could I notify to the parent frame to revalidate? I think in pass the frame to my panel's constructor, but I think may have a way this is already done. I remember that there was a protected attribute in JPanel, but there isn't.. maybe i remembering the wrong component.

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  • spring mvc forward to jsp

    - by jerluc
    I currently have my web.xml configured to catch 404s and send them to my spring controller which will perform a search given the original URL request. The functionality is all there as far as the catch and search go, however the trouble begins to arise when I try to return a view. <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver" p:order="1"> <property name="mediaTypes"> <map> <entry key="json" value="application/json" /> <entry key="jsp" value="text/html" /> </map> </property> <property name="defaultContentType" value="application/json" /> <property name="favorPathExtension" value="true" /> <property name="viewResolvers"> <list> <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" /> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value="" /> </bean> </list> </property> <property name="defaultViews"> <list> <bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" /> </list> </property> <property name="ignoreAcceptHeader" value="true" /> </bean> This is a snippet from my MVC config file. The problem lies in resolving the view's path to the /WEB-INF/jsp/ directory. Using a logger in my JBoss setup, I can see that when I test this search controller by going to a non-existent page, the following occurs: Server can't find the request Request is sent to 404 error page (in this case my search controller) Search controller performs search Search controller returns view name (for this illustration, we'll assume test.jsp is returned) Based off of server logger, I can see that org.springframework.web.servlet.view.JstlView is initialized once my search controller returns the view name (so I can assume it is being picked up correctly by the InternalResourceViewResolver) Server attempts to return content to browser resulting in a 404! A couple things confuse me about this: I'm not 100% sure why this isn't resolving when test.jsp clearly exists under the /WEB-INF/jsp/ directory. Even if there was some other problem, why would this result in a 404? Shouldn't a 404 error page that results in another 404 theoretically create an infinite loop? Thanks for any help or pointers! Controller class [incomplete]: @Controller public class SiteMapController { //-------------------------------------------------------------------------------------- @Autowired(required=true) private SearchService search; @Autowired(required=true) private CatalogService catalog; //-------------------------------------------------------------------------------------- @RequestMapping(value = "/sitemap", method = RequestMethod.GET) public String sitemap (HttpServletRequest request, HttpServletResponse response) { String forwardPath = ""; try { long startTime = System.nanoTime() / 1000000; String pathQuery = (String) request.getAttribute("javax.servlet.error.request_uri"); Scanner pathScanner = new Scanner(pathQuery).useDelimiter("\\/"); String context = pathScanner.next(); List<ProductLightDTO> results = new ArrayList<ProductLightDTO>(); StringBuilder query = new StringBuilder(); String currentValue; while (pathScanner.hasNext()) { currentValue = pathScanner.next().toLowerCase(); System.out.println(currentValue); if (query.length() > 0) query.append(" AND "); if (currentValue.contains("-")) { query.append("\""); query.append(currentValue.replace("-", " ")); query.append("\""); } else { query.append(currentValue + "*"); } } //results.addAll(this.doSearch(query.toString())); System.out.println("Request: " + pathQuery); System.out.println("Built Query:" + query.toString()); //System.out.println("Result size: " + results.size()); long totalTime = (System.nanoTime() / 1000000) - startTime; System.out.println("Total TTP: " + totalTime + "ms"); if (results == null || results.size() == 0) { forwardPath = "home.jsp"; } else if (results.size() == 1) { forwardPath = "product.jsp"; } else { forwardPath = "category.jsp"; } } catch (Exception ex) { System.err.println(ex); } System.out.println("Returning view: " + forwardPath); return forwardPath; } }

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  • Using exponential smoothing with NaN values

    - by Eric
    I have a sample of some kind that can create somewhat noisy output. The sample is the result of some image processing from a camera, which indicates the heading of a blob of a certain color. It is an angle from around -45° to +45°, or a NaN, which means that the blob is not actually in view. In order to combat the noisy data, I felt that exponential smoothing would do the trick. However, I'm not sure how to handle the NaN values. On the one hand, involving them in the math would result in a NaN average, which would then prevent any meaningful results. On the other hand, ignoring NaN values completely would mean that a "no-detection" scenario would never be reported. And just to complicate things, the data is also noisy in that it can get false NaN value, which ideally would be smoothed somehow to prevent random noise. Any ideas about how I could implement such an exponential smoother?

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  • stop thread that does not get interrupted

    - by prmatta
    I have a thread that sits and reads objects off of an ObjectInputStream: public void run() { try { ois = new ObjectInputStream(clientSocket.getInputStream()); Object o; while ((o = ois.readObject()) != null) { //do something with object } } catch (Exception ex) { //Log exception } } readObject does not throw InterruptedException and as far as I can tell, no exception is thrown when this thread is interrupted. How do I stop this thread?

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  • Grails query not using GORM

    - by Tihom
    What is the best way to query for something without using GORM in grails? I have query that doesn't seem to fit in the GORM model, the query has a subquery and a computed field. I posted on stackoverflow already with no response so I decided to take a different approach. I want to query for something not using GORM within a grails application. Is there an easy way to get the connection and go through the result set?

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  • JavaMe Bluetooth service registration

    - by NoGlue
    Hello, I am trying to develope an application that offers a service via bluetooth. Everything works fine in the emulator but as soon I install it on a real device (6120/X6 Nokia) the service cannot be found. If I search for already registered services such as OBEX they are found. So I think it has something to do with the registration. This is how I register the service, all of this happens in its own thread. try { LocalDevice.getLocalDevice().setDiscoverable(DiscoveryAgent.GIAC); } catch (BluetoothStateException e) { } try { notifier = (StreamConnectionNotifier) Connector.open(m_url); ServiceRecord sr = local.getRecord(notifier); StreamConnection conn = notifier.acceptAndOpen(); } catch (IOException e) { } And this is what m_url looks like: "btspp://localhost:" + 0x1116 + ";name=BlueMatch"; Thanks for your time. Best regards

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  • tomcat session replication without multicast

    - by Andreas Petersson
    i am planning to use 2 dedicated root servers rented at a hosting provider. those machines will run tomcat 6 in a cluster. if i will add additional machines later on - it is unlikely that they will be accessible with multicast, because they will be located in different subnets. is it possible to run tomcat without multicast? all tutorials for tomcat 6 clustering include multicast heartbeat. are there any alternatives to SimpleTcpCluster? or are other alternatives more appropriate in this situation?

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  • Casting of object for a class loaded at runtime

    - by Steven
    hi, i load a class using Class.forName(klassname,false,loader) After this i create an instance using klass.newInstance(); It returns an object type.I want to cast it to specific type(ie.Klassnamw instance).I used normal casting but it gets hung because it is not resolved during runtime.How can i cast it?Hellp

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  • How to lowercase every element of a collection efficiently?

    - by Chris
    Whats the most efficient way to lower case every element of a list or set? My idea for a List: final List<String> strings = new ArrayList<String>(); strings.add("HELLO"); strings.add("WORLD"); for(int i=0,l=strings.size();i<l;++i) { strings.add(strings.remove(0).toLowerCase()); } is there a better, faster way? How would this exmaple look like for a set? As there is currently no method for applying an operation to each element of a set (or list) can it be done without creating an additional temporary set? Something like this would be nice: Set<String> strings = new HashSet<String>(); strings.apply( function (element) { this.replace(element, element.toLowerCase();) } ); Thanks,

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  • how to query an embedded entity by using a query builder

    - by user577719
    I've searched quite a time for an answer to this question. Following Codesmell: @Entity public class Person { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) protected Integer id; @Column(nullable = true, length = 50) @Size(max = 50) private String name; @Embedded @Valid protected Adress adress; public void setId(Integer id) { this.id = id; } public Integer getId() { return this.id; } public void setName(String name) { this.name = name; } public void getName() { return this.name; } public void setAdress(Adress adress) { this.adress = adress; } public void getAdress() { return this.adress; } } @Embeddable public class Adress { @Column(nullable = false, length = 50) @Size(max = 50) @NotNull private String place; public void setPlace(String place) { this.place = place; } public void getPlace() { return this.place; } } public class PersonDaoJpa { public List<Ort> findByPerson(final Person person) { CriteriaBuilder builder = this.entityManager.getCriteriaBuilder(); CriteriaQuery<Person> query = builder.createQuery(Person.class); Root<Person> rootPerson = query.from(Person.class); List<Predicate> wherePredicates = new ArrayList<Predicate>(); if (person.getName() != null) { wherePredicates.add( builder.like(builder.lower(rootPerson.<String>get("name")), ort.getName().toLowerCase()) ); } Adresse adresse = ort.getAdresse(); if (adresse != null) { if(adresse.getPlace() != null) { // this won't work wherePredicates.add( builder.like(builder.lower(rootPerson.<String>get("person.adress.place")), adresse.getPlace().toLowerCase()) ); } } Predicate whereClause = builder.and(wherePredicates.toArray(new Predicate[0])); query.where(whereClause); return this.entityManager.createQuery(query).getResultList(); } } How can I access the Adress.place through rootPerson? rootPerson.get("place"), or rootPerson.get("adress.place") won't work...

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  • Strange problems with the Spring RestTemplate in Android application

    - by HarryCater
    I begin to use RESTful api of the Spring Framework in my android client application. But I have encountered with problems when I tried to execute HTTP request via postForObject/postForEntity methods. Here is my code: public String _URL = "https://noticemed.com/app/mobile/login"; public void BeginAuthorization(View view) { HttpHeaders requestHeaders = new HttpHeaders(); requestHeaders.setContentType(MediaType.APPLICATION_JSON); HttpEntity<String> _entity = new HttpEntity<String>(requestHeaders); RestTemplate templ = new RestTemplate(); templ.setRequestFactory(new HttpComponentsClientHttpRequestFactory()); templ.getMessageConverters().add(new MappingJacksonHttpMessageConverter()); ResponseEntity<String> _response = templ.postForEntity(_URL,_entity,String.class); //HERE APP CRASHES String _body = _response.getBody(); And here is a stack trace in logcat after app crashing. As you see there is no definite error message. So the question what am I doing wrong? How to fix this? May there is other way to do it?I really need a help. Thanks in advance!

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  • How to create updateable panel using AjaxLink of Wicket?

    - by Arne
    I try to realize a link (in fact many links) that update a table in an website using an AjaxLink of Wicket. But I fail, the table is never updated (I have "setOutputMarkupId(true)" and call "addComponent", but there must be something other thats wrong). How can I realize a panel with a number of links and a table that displays dynamic data, dependent on the link clicked? Can someone give an example (Maybe two links, when the first one is clicked the table displays two random numbers from 1-10, when the second is clicked the table displays random numbers from 1-100)? Without reloading the entire page, but only the html for the table?

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  • Blackberry app development - Drawing graphics on top of rendered text/buttons etc

    - by paullb
    Based off the one of the demos I have the following code. Currently what displays in the simulator is just hte contents of the paint function, however the ObjectChoiceField is still selectable if one happens to click in the right location. I would like both the text contents and the paint function contents to appear. Is this possible? public CityInfoScreen() { //invoke the MainScreen constructor super(); //add a screen title LabelField title = new LabelField("City Information Kiosk", LabelField.ELLIPSIS | LabelField.USE_ALL_WIDTH); setTitle(title); //add a text label add(new RichTextField("Major U.S. Cities")); //add a drop-down list with three choices: //Los Angeles, Chicago, or New York //... String choices[] = {"Los Angeles","Chicago","New York"}; choiceField = new ObjectChoiceField("select a city", choices); add(choiceField); Manager man = this.getMainManager(); } ... public void paint(Graphics g){ super.paint(g); // g.drawRect(0,left,500,500+left); g.setGlobalAlpha(0); g.drawRect(100-left,100-top,200,200); String text = new Integer(left).toString(); String text2 = new Integer(top).toString(); g.drawText(text + " " + text2,120-left,120-top); }

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