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  • Java HotSpot 1.6 VM, Garbage Collection - Scary PermGen

    - by Gala101
    Hi, My app shows rising 'Old Generation'/'Tenured Generation' size, and when this reaches the max limit for 'Old Gen', then suddenly PermGen size increases. Here are my generation sizings: -Xmx1200m -Xms1200m -Xmn450m -XX:MaxPermSize=600m -XX:+UseParallelGC This is on 32 bit Fedora so can't have a bigger heap than this. The app is not doing any fancy classloading, though it is using Spring IOC and Hibernate, the Spring App-context.xml defines some 1000 Beans. This app starts with 175MB PermGen, which steadily increases to ~250MB in few hrs, stays that way till Tenured Generation reached ~780 MB, then permgen jumps to ~500MB while Old Gen drops to ~500MB. This forces me to restart the App on daily basis, and gives me real scare of looming OutOfMemory Error.. Any insights would be very helpful. Thanks Gala101

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  • What's "@Override" there for in java?

    - by symfony
    public class Animal { public void eat() { System.out.println("I eat like a generic Animal."); } } public class Wolf extends Animal { @Override public void eat() { System.out.println("I eat like a wolf!"); } } Does @Override actually have some functionality or it's just kinda comment?

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  • Java resource closing

    - by Bob
    Hi, I'm writing an app that connect to a website and read one line from it. I do it like this: try{ URLConnection connection = new URL("www.example.com").openConnection(); BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream())); String response = rd.readLine(); rd.close(); }catch (Exception e) { //exception handling } Is it good? I mean, I close the BufferedReader in the last line, but I do not close the InputStreamReader. Should I create a standalone InputStreamReader from the connection.getInputStream, and a BufferedReader from the standalone InputStreamReader, than close all the two readers? I think it will be better to place the closing methods in the finally block like this: InputStreamReader isr = null; BufferedReader br = null; try{ URLConnection connection = new URL("www.example.com").openConnection(); isr = new InputStreamReader(connection.getInputStream()); br = new BufferedReader(isr); String response = br.readLine(); }catch (Exception e) { //exception handling }finally{ br.close(); isr.close(); } But it is ugly, because the closing methods can throw exception, so I have to handle or throw it. Which solution is better? Or what would be the best solution?

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  • Java Static Methods

    - by KP65
    Hello, I am wondering when to use static methods? Say If i have a class with a few getters and setters, a method or two, and i want those methods only to be invokable on an instance object of the class. Does this mean i should use a static method? e.g Obj x = new Obj(); x.someMethod or Obj.someMethod (is this the static way?) I'm rather confused!

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  • getting base64 content string of an image from a mimepart in Java

    - by Bas van den Broek
    Hello, I am trying to get the base64 content of a MimePart in a MimeMultiPart, but I'm struggling with the Javamail package. I simply want the base64 encoded String of a certain inline image, there doesn't seem to be an easy way to do this though. I wrote a method that will take the mime content (as a string) and an image name as a parameter, and searches for the part that contains the base64 content of that image name, and in the end returns this base64 string (as well as the content type but that is irrelevant for this question) Here is the relevant code: private static String[] getBase64Content(String imageName, String mimeString) throws MessagingException, IOException { System.out.println("image name: " + imageName + "\n\n"); System.out.println("mime string: " + mimeString); String[] base64Content = new String[2]; base64Content[0] = ""; base64Content[1] = "image/jpeg"; //some default value DataSource source = new ByteArrayDataSource(new ByteArrayInputStream(mimeString.getBytes()), "multipart/mixed"); MimeMultipart mp = new MimeMultipart(source); for (int i = 0; i < mp.getCount(); i++) { MimePart part = (MimePart) mp.getBodyPart(i); String disposition = part.getDisposition(); if (disposition != null && disposition.equals(Part.INLINE)) { if (part.getContentID() != null && part.getContentID().indexOf(imageName) > -1) //check if this is the right part { if (part.getContent() instanceof BASE64DecoderStream) { BASE64DecoderStream base64DecoderStream = (BASE64DecoderStream) part.getContent(); StringWriter writer = new StringWriter(); IOUtils.copy(base64DecoderStream, writer); String base64decodedString = writer.toString(); byte[] encodedMimeByteArray = Base64.encodeBase64(base64decodedString.getBytes()); String encodedMimeString = new String(encodedMimeByteArray); System.out.println("encoded mime string: " + encodedMimeString); base64Content[0] = encodedMimeString; base64Content[1] = getContentTypeString(part); } } } } return base64Content; } I cannot paste all of the output as the post would be too long, but this is some of it: image name: [email protected] This is a part of the mimeString input, it does find this (correct) part with the image name: --_004_225726A14AF9134CB538EE7BD44373A04D9E3F3940menexch2007ex_ Content-Type: image/gif; name="image001.gif" Content-Description: image001.gif Content-Disposition: inline; filename="image001.gif"; size=1070; creation-date="Fri, 02 Apr 2010 16:19:43 GMT"; modification-date="Fri, 02 Apr 2010 16:19:43 GMT" Content-ID: <[email protected]> Content-Transfer-Encoding: base64 R0lGODlhEAAQAPcAABxuHJzSlDymHGy2XHTKbITCdNTu1FyqTHTCXJTKhLTarCSKHEy2JHy6bJza lITKfFzCPEyWPHS+XHzCbJzSjFS+NLTirBx6HHzKdOz27GzCZJTOjCyWHKzWpHy2ZJTGhHS+VLzi (more base64 string here that I'm not going to paste) But when it finally prints the encoded mime string, this is a different string than I was expecting: encoded mime string: R0lGODlhEAAQAO+/vQAAHG4c77+90pQ877+9HGzvv71cdO+/vWzvv73vv71077+977+977+9XO+/vUx077+9XO+/vcqE77+92qwk77+9HEzvv70kfO+/vWzvv73alO+ Clearly different from the one that has its output in the part above. I'm not even sure what I'm looking at here, but when I try to load this as an image in a html page, it won't work. This is fairly frustrating for me, since all I want is a piece of the text that I'm already printing, but I'd rather not have to search through the mime string myself for the correct part, introducing all kinds of bugs.So I'd really prefer to use the Javamail library but could use some help on how to actually get that correct mime string.

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  • Task Queue Java API

    - by user268515
    Hi when i started to work on Task queue concept i got struck on this line queue.add( DatastoreServiceFactory.getDatastoreService().getCurrentTransaction(), TaskOptions().url("/path/to/my/worker")); What will DatastoreServiceFactory do... How to redirect this page to another servlet.... in the url i gave .url("/myservlet") but it doesn't redirected to servlet Please say what should given in .url.Help me. Regards, sharun

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  • Casting and dynamic vs static type in Java

    - by XpdX
    I'm learning about static vs dynamic types, and I am to the point of understanding it for the most part, but this case still eludes me. If class B extends A, and I have: A x = new B(); Is the following allowed?: B y = x; Or is explicit casting required?: B y = (B)x; Thanks!

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  • Java remove HTML from String without regular expressions

    - by behrk2
    Hello, I am trying to remove all HTML elements from a String. Unfortunately, I cannot use regular expressions because I am developing on the Blackberry platform and regular expressions are not yet supported. Is there any other way that I can remove HTML from a string? I read somewhere that you can use a DOM Parser, but I couldn't find much on it. Text with HTML: <![CDATA[As a massive asteroid hurtles toward Earth, NASA head honcho Dan Truman (<a href="http://www.netflix.com/RoleDisplay/Billy_Bob_Thornton/20000303">Billy Bob Thornton</a>) hatches a plan to split the deadly rock in two before it annihilates the entire planet, calling on Harry Stamper (<a href="http://www.netflix.com/RoleDisplay/Bruce_Willis/99786">Bruce Willis</a>) -- the world's finest oil driller -- to head up the mission. With time rapidly running out, Stamper assembles a crack team and blasts off into space to attempt the treacherous task. <a href="http://www.netflix.com/RoleDisplay/Ben_Affleck/20000016">Ben Affleck</a> and <a href="http://www.netflix.com/RoleDisplay/Liv_Tyler/162745">Liv Tyler</a> co-star.]]> Text without HTML: As a massive asteroid hurtles toward Earth, NASA head honcho Dan Truman (Billy Bob Thornton) hatches a plan to split the deadly rock in two before it annihilates the entire planet, calling on Harry Stamper (Bruce Willis) -- the world's finest oil driller -- to head up the mission. With time rapidly running out, Stamper assembles a crack team and blasts off into space to attempt the treacherous task.Ben Affleck and Liv Tyler co-star. Thanks!

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  • Java Generic Casting Type Mismatch

    - by Kay
    public class MaxHeap<T extends Comparable<T>> implements Heap<T>{ private T[] heap; private int lastIndex; public void main(String[] args){ int i; T[] arr = {1,3,4,5,2}; //ERROR HERE ******* foo } public T[] Heapsort(T[]anArray, int n){ // build initial heap T[]sortedArray = anArray; for (int i = n-1; i< 0; i--){ //assert: the tree rooted at index is a semiheap heapRebuild(anArray, i, n); //assert: the tree rooted at index is a heap } //sort the heap array int last = n-1; //invariant: Array[0..last] is a heap, //Array[last+1..n-1] is sorted for (int j=1; j<n-1;j++) { sortedArray[0]=sortedArray[last]; last--; heapRebuild(anArray, 0, last); } return sortedArray; } protected void heapRebuild(T[ ] items, int root, int size){ foo } } The error is on the line with "T[arr] = {1,3,4,5,2}" Eclispe complains that there is a: "Type mismatch: cannot convert from int to T" I've tried to casting nearly everywhere but to no avail.A simple way out would be to not use generics but instead just ints but that's sadly not an option. I've got to find a way to resolve the array of ints "{1,3,4,5,2}" into an array of T so that the rest of my code will work smoothly.

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  • java casting confusion

    - by Stardust
    Could anyone please tell me why the following casting is resulting in compile time error: Long l = (Long)Math.pow(5,2); But why not the following: long l = (long)Math.pow(5,2);

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  • Java basic authorization with URLConnection

    - by zigomir
    Hello! I'm opening a connection to WebService with an URLConnection class. I also set request property for basic authorization like this: c.setRequestProperty("Authorization", "Basic " + usernameAndPasswordEncoded); Where c is an object of type URLConnection. So this is client side of WebService call. Now on server side I need to get username from session: User user = (User) request.getSession().getAttribute("user"); But this won't get an username. Also if I look through debug mode, I see an anonymous userName in HttpSession object. What to do to solve this problem, so that username is sent through client to WebService server for authorization? Thanks everyone!

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  • Java - Custom PropertyEditorSupport to display units

    - by I82Much
    All, I'm trying to make the properties of my node have Units associated with the measure. ( I am using the JScience.org implementation of JSR 275) So for instance, public class Robot extends AbstractNode { // in kg float vehicleMass; @Override public Sheet createSheet() { Sheet s = Sheet.createDefault(); Sheet.Set set = s.createPropertiesSet(); try { PropertySupport.Reflection vehicleMassField = new PropertySupport.Reflection(this, float.class, "vehicleMass"); vehicleMassField.setValue("units", SI.KILOGRAMS); vehicleMassField.setName("vehicleMass"); set.put(vehicleMassField); PropertyEditorManager.registerEditor(float.class, UnitInPlaceEditor.class); } catch (NoSuchMethodException ex) { Exceptions.printStackTrace(ex); } s.put(set); return s; } } I want my UnitInPlaceEditor to append the units to the end of the string representation of the number, and when the field is clicked (enters edit mode) for the units to disappear and just the number becomes selected for editing. I can make the units appear, but I cannot get the units to disappear when the field enters editing mode. public class UnitsInplaceEditor extends PropertyEditorSupport implements ExPropertyEditor { private PropertyEnv pe; @Override public String getAsText() { // Append the unit by retrieving the stored value } @Override public void setAsText(String s) { // strip off the unit, parse out the number } public void attachEnv(PropertyEnv pe) { this.pe = pe; } } Here's a screenshot of the display - I like it like this.. but here's the value being edited; note the unit stays there. Basically I want one value (string) to be displayed in the field when the field is NOT being edited, and a different to be displayed when user starts editing the field. Barring that, I'd like to put a constant jlabel for the units (uneditable) to the right of the text field. Anyone know how to do this?

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  • What is faster- Java or C# (Or good old C)?

    - by Rexsung
    I'm currently deciding on a platform to build a scientific computational product on, and am deciding on either C#, Java, or plain C with Intels compiler on Core2 Quad CPU's. It's mostly integer arithmetic. My benchmarks so far show Java and C are about on par with each other, and dotNET/C# trails by about 5%- however a number of my coworkers are claiming that dotNET with the right optimizations will beat both of these given enough time for the JIT to do its work. I always assume that the JIT would have done it's job within a few minutes of the app starting (Probably a few seconds in my case, as it's mostly tight loops), so I'm not sure whether to believe them Can anyone shed any light on the situation? Would dotNET beat Java? (Or am I best just sticking with C at this point?). The code is highly multithreaded and data sets are several terabytes in size. Haskell/erlang etc are not options in this case as there is a significant quantity of existing legacy C code that will be ported to the new system, and porting C to Java/C# is a lot simpler than to Haskell or Erlang. (Unless of course these provide a significant speedup). Edit: We are considering moving to C# or Java because they may, in theory, be faster. Every percent we can shave off our processing time saves us tens of thousands of dollars per year. At this point we are just trying to evaluate whether C, Java, or c# would be faster.

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  • [java] Trying to use ResourceBundle to fetch messages from external file

    - by bumperbox
    Essentially I would like to have a messages.properties files external to the jar files in my application. So that users can add languages and edit the files easily if my translations are wrong at the moment i use ResourceBundle.getBundle("package.MessageBundle"); But i would like to do something like this ResourceBundle.getBundle("lang/MessageBundle"); Where lang is a folder under my application installation directory. is this a good idea (if not, why not)? can someone point me in the right direction, or some sample code that does this thanks Alex

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  • J2EE fast track (Learning Enterprise Java real fast)

    - by IndexController
    Hello, We just started a new project in J2EE in our office and i am required to participate effectively. I mostly work on web applications and I use PHP/MySql but I also know J2SE and have written couple of standalone applications. I need help and advise on how i can learn J2ee very fast so that i can blend into the project without difficulties. I need help with book & tutorial recommendations and also links to resources. Thank you for your time.

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  • Java mail attachment not working on Tomcat

    - by losintikfos
    Hello guys, I have an application which e-mails confirmations. The email part utilises Commons Mail API. The simple code which does the send mail is as shown below; import org.apache.commons.mail.*; ... // Create the attachment EmailAttachment attachment = new EmailAttachment(); attachment.setURL(new URL("http://cashew.org/doc.pdf")); attachment.setDisposition(EmailAttachment.ATTACHMENT); attachment.setDescription("Testing attach"); attachment.setName("doc.pdf"); // Create the email message MultiPartEmail email = new MultiPartEmail(); email.setHostName("mail.cashew.com"); email.addTo("[email protected]"); email.setFrom("[email protected]"); email.setSubject("Testing); email.setMsg("testing message"); // add the attachment email.attach(attachment); // send the email email.send(); My problem is, when I execute this application from Eclipse, I get email sent with attachment without any issues. But when i deploy the application to Tomcat server (I have tried both version 5 & 6 no joy), the e-mail is sent with below content; ------=_Part_0_25002283.1275298567928 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit testing Regards, los ------=_Part_0_25002283.1275298567928 Content-Type: application/pdf; name="doc.pdf" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="doc.pdf" Content-Description: Testing attach JVBERi0xLjQNJeLjz9MNCjYzIDAgb2JqDTw8L0xpbmVhcml6ZWQgMS9MIDMxMzE4Mi9PIDY1L0Ug Mjg2NjY5L04gMS9UIDMxMTgwMi9IIFsgMjgzNiAzNzZdPj4NZW5kb2JqDSAgICAgICAgICAgICAg DQp4cmVmDQo2MyAxMjcNCjAwMDAwMDAwMTYgMDAwMDAgbg0KMDAwMDAwMzM4MCAwMDAwMCBuDQow MDAwMDAzNTIzIDAwMDAwIG4NCjAwMDAwMDQzMDcgMDAwMDAgbg0KMDAwMDAwNTEwOSAwMDAwMCBu DQowMDAwMDA2Mjc5IDAwMDAwIG4NCjAwMDAwMDY0MTAgMDAwMDAgbg0KMDAwMDAwNjU0NiAwMDAw MCBuDQowMDAwMDA3OTY3IDAwMDAwIG4NCjAwMDAwMDkwMjMgMDAwMDAgbg0KMDAwMDAwOTk0OSAw MDAwMCBuDQowMDAwMDExMDAwIDAwMDAwIG4NCjAwMDAwMTIwNTkgMDAwMDAgbg0KMDAwMDAxMjky MCAwMDAwMCBuDQowMDAwMDEyOTU0IDAwMDAwIG4NCjAwMDAwMTI5ODIgMDAwMDAgbg0KMDAwMDAx ....... CnN0YXJ0eHJlZg0KMTE2DQolJUVPRg0K ------=_Part_0_25002283.1275298567928-- One thing also I have noticed is, the header information donot show TO and Subject values. Hmm pretty wierd. I have to point out that, above is not generated of DEBUG, it is the actual message recieved in my outlook client. Can someone help me please! Do anyone knows what's going on?

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  • Java - Class type from inside static initialization block

    - by DutrowLLC
    Is it possible to get the class type from inside the static initialization block? This is a simplified version of what I currently have:: class Person extends SuperClass { String firstName; static{ // This function is on the "SuperClass": // I'd for this function to be able to get "Person.class" without me // having to explicitly type it in but "this.class" does not work in // a static context. doSomeReflectionStuff(Person.class); // IN "SuperClass" } } This is closer to what I am doing, which is to initialize a data structure that holds information about the object and its annotations, etc... Perhaps I am using the wrong pattern? public abstract SuperClass{ static void doSomeReflectionStuff( Class<?> classType, List<FieldData> fieldDataList ){ Field[] fields = classType.getDeclaredFields(); for( Field field : fields ){ // Initialize fieldDataList } } } public abstract class Person { @SomeAnnotation String firstName; // Holds information on each of the fields, I used a Map<String, FieldData> // in my actual implementation to map strings to the field information, but that // seemed a little wordy for this example static List<FieldData> fieldDataList = new List<FieldData>(); static{ // Again, it seems dangerous to have to type in the "Person.class" // (or Address.class, PhoneNumber.class, etc...) every time. // Ideally, I'd liken to eliminate all this code from the Sub class // since now I have to copy and paste it into each Sub class. doSomeReflectionStuff(Person.class, fieldDataList); } }

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  • Problem with Gregorian Calendar hour of day in java

    - by Leanne C
    hi, I'm using a Gregorian Calendar to set a specific date and time to an application using the set function of the Gregorian Calendar. When i use the getTime() method, it gives me the right output however when i try to access the Hour_Of_Day and Minute it gives a wrong number. Calendar time = new GregorianCalendar(); time.set(2010, Calendar.JANUARY, 1, 7, 20,0); hour = time.HOUR_OF_DAY; minute = time.MINUTE; The hour gives an output of 11 and the minute gives an a value of 12. Any suggestions on how to fix this? Thanks

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  • Java - getConstructor() ?

    - by msr
    Hello, I wrote the question as a comment in the code, I think its easier to understand this way. public class Xpto{ protected AbstractClass x; public void foo(){ // AbstractClass y = new ????? Car or Person ????? /* here I need a new object of this.x's type (which could be Car or Person) I know that with x.getClass() I get the x's Class (which will be Car or Person), however Im wondering how can I get and USE it's contructor */ // ... more operations (which depend on y's type) } } public abstract class AbstractClass { } public class Car extends AbstractClass{ } public class Person extends AbstractClass{ }

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  • How to add an image dynamically at runtime in java

    - by Brandon
    I've been trying to load up an image dynamically in runtime for the longest time and have taken a look at other posts on this site and have yet to find exactly the thing that will work. I am trying to load an image while my GUI is running (making it in runtime) and have tried various things. Right now, I have found the easiest way to create an image is to use a JLabel and add an ImageIcon to it. This has worked, but when I go to load it after the GUI is running, it fails saying there is a "NullPointerException". Here is the code I have so far: p = Runtime.getRuntime().exec("python C:\\FaceVACS\\roc.py " + "C:/FaceVACS/OutputCMC_" + target + ".txt " + "C:/FaceVACS/ROC_" + target + ".png"); Icon graph = new ImageIcon("C:\\FaceVACS\\OutputCMC_" + target + ".png"); roc_image.setIcon(graph); panel.add(roc_image); panel.revalidate(); gui.frame.pack(); I tried panel.validate(), panel.revalidate(), and I've also tried gui.getRootPane(), but I can't seem to find anything that will work. Any ideas would be helpful! Thanks

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