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  • Why does appending "" to a String save memory?

    - by hsmit
    I used a variable with a lot of data in it, say String data. I wanted to use a small part of this string in the following way: this.smallpart = data.substring(12,18); After some hours of debugging (with a memory visualizer) I found out that the objects field smallpart remembered all the data from data, although it only contained the substring. When I changed the code into: this.smallpart = data.substring(12,18)+""; ..the problem was solved! Now my application uses very little memory now! How is that possible? Can anyone explain this? I think this.smallpart kept referencing towards data, but why? UPDATE: How can I clear the big String then? Will data = new String(data.substring(0,100)) do the thing?

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  • Turning off hibernate logging console output

    - by Jared
    I'm using hibernate 3 and want to stop it from dumping all the startup messages to the console. I tried commenting out the stdout lines in log4j.properties but no luck. I've pasted my log file below. Also I'm using eclipse with the standard project structure and have a copy of log4j.properties in both the root of the project folder and the bin folder. ### direct log messages to stdout ### #log4j.appender.stdout=org.apache.log4j.ConsoleAppender #log4j.appender.stdout.Target=System.out #log4j.appender.stdout.layout=org.apache.log4j.PatternLayout #log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n ### direct messages to file hibernate.log ### log4j.appender.file=org.apache.log4j.FileAppender log4j.appender.file.File=hibernate.log log4j.appender.file.layout=org.apache.log4j.PatternLayout log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n ### set log levels - for more verbose logging change 'info' to 'debug' ### log4j.rootLogger=warn, stdout #log4j.logger.org.hibernate=info log4j.logger.org.hibernate=debug ### log HQL query parser activity #log4j.logger.org.hibernate.hql.ast.AST=debug ### log just the SQL #log4j.logger.org.hibernate.SQL=debug ### log JDBC bind parameters ### log4j.logger.org.hibernate.type=info #log4j.logger.org.hibernate.type=debug ### log schema export/update ### log4j.logger.org.hibernate.tool.hbm2ddl=debug ### log HQL parse trees #log4j.logger.org.hibernate.hql=debug ### log cache activity ### #log4j.logger.org.hibernate.cache=debug ### log transaction activity #log4j.logger.org.hibernate.transaction=debug ### log JDBC resource acquisition #log4j.logger.org.hibernate.jdbc=debug ### enable the following line if you want to track down connection ### ### leakages when using DriverManagerConnectionProvider ### #log4j.logger.org.hibernate.connection.DriverManagerConnectionProvider=trac5

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  • Why aren't APT generated classes being compiled by Eclipse?

    - by yamsha
    In my Eclipse project I'm using a third-party annotation processor, Hibernate Metamodel Generator to be exact. The annotation processor works as expected and generates files as specified by the spec. These files are generated inside the directory of the Eclipse project under a "gen" folder. In the project properties this is correctly reflected since two source folders exist - "src" and "gen." However, when the project is built for some reason all the [generated] sources under "gen" are not compiled (checking the "bin" directory I only see .class file from the "src" directory). Does anyone know why this is happening?

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  • best way to pick a random subset from a collection?

    - by Tom
    I have a set of objects in a Vector from which I'd like to select a random subset (e.g. 100 items coming back; pick 5 randomly). In my first (very hasty) pass I did an extremely simple and perhaps overly clever solution: Vector itemsVector = getItems(); Collections.shuffle(itemsVector); itemsVector.setSize(5); While this has the advantage of being nice and simple, I suspect it's not going to scale very well, i.e. Collections.shuffle() must be O(n) at least. My less clever alternative is Vector itemsVector = getItems(); Random rand = new Random(System.currentTimeMillis()); // would make this static to the class List subsetList = new ArrayList(5); for (int i = 0; i < 5; i++) { // be sure to use Vector.remove() or you may get the same item twice subsetList.add(itemsVector.remove(rand.nextInt(itemsVector.size()))); } Any suggestions on better ways to draw out a random subset from a Collection?

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  • Unexpected JAXB error

    - by Mark Lewis
    Hello, From the documentation it's clear I need to use the following to get a simple unmarshalling to occur from my XML file/schema: JAXBContext jc = JAXBContext.newInstance("PackageName"); where PackageName is my package name. I've looked on google for a bit to no avail, to find out why I'm then getting this runtime error: Line:Col[2:142]:cvc-elt.1: Cannot find the declaration of element 'myconfig'. Line:Col[2:142]:unexpected element (uri:"http://www.w3.org", local:"myconfig"). Expected elements are <{}myconfig> Caught UnmarshalException This occurs at the top of all my class files, including the ones the XJC plugin for eclipse created for me (which I then moved out of PackageName.PackageName which it automatically created): package PackageName; so why is this error occurring?

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  • simpledateformat parsing date with 'Z' literal

    - by DanInDC
    I am trying to parse a date that looks like this: 2010-04-05T17:16:00Z This is a valid date per http://www.ietf.org/rfc/rfc3339.txt. The 'Z' literal "imply that UTC is the preferred reference point for the specified time." If I try to parse it using SimpleDateFormat and this pattern: yyyy-MM-dd'T'HH:mm:ss It will be parsed as a Mon Apr 05 17:16:00 EDT 2010 SimpleDateFormat is unable to parse the string with these patterns: yyyy-MM-dd'T'HH:mm:ssz yyyy-MM-dd'T'HH:mm:ssZ I can explicitly set the TimeZone to use on the SimpleDateFormat to get the expected output, but I don't think that should be necessary. Is there something I am missing? Is there an alternative date parser?

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  • Creating a web-service client directly from the source

    - by ben
    Hi, I am trying to generate the WS client jar directly from the @Webservice class(es). Let's take this example : package com.example.maven.jaxws.helloservice; import javax.jws.WebService; @WebService public class Hello { public String sayHello(String param) { ; return "Hello " + param; } } I can generate a war file and use glassfish to serve this webservice, and from there I can use the glassfish WSDL URL to generate the client sources. What I am trying to do is to skip the glassfish part. From my maven project defining the webservice, I would like to use the jaxws-maven-plugin to create the client classes but I cannot find any way to specify the actual URL of the webservice. It should be possible right? @see also http://stackoverflow.com/questions/2097789/creating-a-web-service-client-with-a-known-but-inaccessible-wsdl

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  • Placing figure in top-right corner of another

    - by Ivan Dubrov
    I want child figure (org.eclipse.draw2d.Figure) to be relative to the top-right corner of the parent (I want place some small icon, which will be ImageFigure, to be 12 pixels from top and right borders). Is there an existing layout manager that can layout child this way? The org.eclipse.draw2d.XYLayout is not capable of measuring position relative to corner other than top-left. Of course, I can: Write layout manager myself Layout children figure every time bounds are changed for the parent (in parent layout() method). However, I would like to know if some existing layout manager provides that functionality.

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  • TreeMap not properly returning values

    - by smessing
    I have the following TreeMap: TreeMap<String, Integer> distances = new TreeMap<String, Integer>(); and it contains both strings, "Face" and "Foo", with appropriate values, such that: System.out.println(distances); Yields: {Face=12, Foo=2} However, distances.get(Face) returns null, even though distances.get(Foo) properly returns 2. Previously, distances.get(Face) worked, but for some reason, it stopped working. Note I print out the map right before calling get() for both keys, so I haven't accidentally changed Face's value to null. Has anyone else every encountered this problem? Is there anything I can do? I'm having a terrible time simply trying to figure out how to debug this problem.

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  • RSA public key exportation

    - by user308806
    Dear all, Here is my code KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA"); KeyPair myPair = kpg.generateKeyPair(); PrivateKey k = myPair.getPrivate(); System.out.print(k.serialVersionUID); Cipher c = Cipher.getInstance("RSA"); c.init(Cipher.ENCRYPT_MODE, myPair.getPublic()); String myMessage = new String("Testing the message"); byte[] bytes = c.doFinal(myMessage.getBytes()); String tt = new String(bytes); System.out.println(tt); Cipher d = Cipher.getInstance("RSA"); d.init(Cipher.DECRYPT_MODE, myPair.getPrivate()); byte[] temp = d.doFinal(bytes); String tst = new String(temp); System.out.println(tst); My question is how can i get the public key and stored elsewhere

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  • Hibernate: Dirty Checking and Only Update of Dirty Attributes?

    - by jens
    Hello Experts, in "good old JDBC days" I wrote a lot of SQL Queries that did very targeted updates of only the "attributes/members" that were actually changed: For Example having an object with the following members: public String name; public String address; public Date date; If only date was changed in some Business Method I would only issue an SQL UPDATE for the date member. ==It seems however (thats my "impression" of hibernate) that when working with a standard Hibernate mapping (mapping the full class), even updates of only one single member lead to a full update of the object in SQL Statements generated by Hibernate. My Questions are: 1.) Is this observation correct, that hibernate DOES NOT intelligently check (in a fully mapped class), what member(s) where changed and then only issue updates for the specific changed members, but rather always will update (in the generated SQL Update Statement) all mapped members (of a class), even if they were not changed (in case the object is dirty due to one member being dirty...) 2.) What can I do to make Hibernate only update those members, that have been changed? I am searching for a solution to have hibernate only update the member that actually changed. (I know hibernate does some big work on doing dirty-checking, but as far as I know this dirtychecking is only relevant to identify if the object as whole is dirty, not what single member is dirty.) Thank you very much! Jens

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  • Confused as to how to validate spring mvc form, what are my options?

    - by Blankman
    Latest spring mvc, using freemarker. Hoping someone could tell me what my options are in terms of validating a form with spring mvc, and what the recommend way would be to do this. I have a form that doesn't map directly to a model, it has input fields that when posted, will be used to initialze 2 model objects which I will then need to validate, and if they pass I will save them. If they fail, I want to return back to the form, pre-fill the values with what the user entered and display the error messages. I have read here and there about 2 methods, once of which I have done and understand how it works: @RequestMapping(...., method = RequestMethod.POST) public ModelAndView myMethod(@Valid MyModel, BindingResult bindingResult) { ModelAndView mav = new ModelAndView("some/view"); mav.addObject("mymodel", myModel); if(bindingResult.hasErrors()) { return mav; } } Now this worked if my form mapped directly to the form, but in my situation I have: form fields that don't map to any specific model, they have a few properties from 2 models. before validation occurrs, I need to create the 2 models manually, set the values from the values from the form, and manually set some properties also: Call validate on both models (model1, model2), and append these error messages to the errors collection which I need to pass back to the same view page if things don't work. when the form posts, I have to do some database calls, and based on those results may need to add additional messages to the errors collection Can someone tell me how to do this sort of validation? Pseudo code below: Model1 model1 = new Model1(); Model2 model2 = new Model2(); // manually or somehow automatically set the posted form values to model1 and model2. // set some fields manually, not from posted form model1.setProperty10(GlobalSettings.getDefaultProperty10()); model2.setProperty11(GlobalSettings.getDefaultProperty11()); // db calls, if they fail, add to errors collection if(bindingResult.hasErrors()) { return mav; } // validation passed, save Model1Service.save(model1); Model2Service.save(model2); redirect to another view Update I have using the JSR 303 annotations on my models right now, and it would great if I can use those still. Update II Please read the bounty description below for a summary of what I am looking for.

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  • JBoss ignores @RemoteBinding annotation

    - by tputkonen
    I would like to specify JNDI name for an EJB3 bean using annotation, but JBoss 5.1.0 GA seems to ignore the annotation completely. Bean's annotations are: @Remote(Foobar.class) @Stateless(name = "Foobar") @TransactionManagement(TransactionManagementType.BEAN) @RemoteBinding(jndiBinding="ejb/Foobar") public class FoobarBean implements Foobar { ... I tested deploying also using @RemoteBindings annotation, but the result was same: @RemoteBindings({@RemoteBinding(jndiBinding="ejb/Foobar")}) The bean does not get bound to JNDI with the specified name, and the log file doesn't give any clues.

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  • Is there a library for editing program flow?

    - by Iulian Serbanoiu
    Hello, I was wondering if there is a library for editing program flow. I refer to conditions if, loops (do, while, for) and other elements that can exist inside a program. What I would like to have is some sort of a CAD application (similar to an UML editor) from where I can take some elements and edit their properties, make connections between them. Do you know similar software that does this, or resembles a little what I'm trying to achieve? Thanks, Iulian PS: It is something that should resemble this image. PS2: I want to write code for doing this, I was wondering if such things exist.

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  • Best Maven plugins

    - by ripper234
    We are just moving to Maven, and I understand there is a world of different plugins & extensions. Which are the best ones you recommend for general usage? (On plugin per answer please)

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  • OSGI Declarative Services (DS): What is a good way of using service component instances

    - by Christoph
    I am just getting started with OSGI and Declarative Services (DS) using Equinox and Eclipse PDE. I have 2 Bundles, A and B. Bundle A exposes a component which is consumed by Bundle B. Both bundles also expose this service to the OSGI Service registry again. Everything works fine so far and Equinox is wireing the components together, which means the Bundle A and Bundle B are instanciated by Equinox (by calling the default constructor) and then the wireing happens using the bind / unbind methods. Now, as Equinox is creating the instances of those components / services I would like to know what is the best way of getting this instance? So assume there is third class class which is NOT instantiated by OSGI: Class WantsToUseComponentB{ public void doSomethingWithComponentB(){ // how do I get componentB??? Something like this maybe? ComponentB component = (ComponentB)someComponentRegistry.getComponent(ComponentB.class.getName()); } I see the following options right now: 1. Use a ServiceTracker in the Activator to get the Service of ComponentBundleA.class.getName() (I have tried that already and it works, but it seems to much overhead to me) and make it available via a static factory methods public class Activator{ private static ServiceTracker componentBServiceTracker; public void start(BundleContext context){ componentBServiceTracker = new ServiceTracker(context, ComponentB.class.getName(),null); } public static ComponentB getComponentB(){ return (ComponentB)componentBServiceTracker.getService(); }; } 2. Create some kind of Registry where each component registers as soon as the activate() method is called. public ComponentB{ public void bind(ComponentA componentA){ someRegistry.registerComponent(this); } or public ComponentB{ public void activate(ComponentContext context){ someRegistry.registerComponent(this); } } } 3. Use an existing registry inside osgi / equinox which has those instances? I mean OSGI is already creating instances and wires them together, so it has the objects already somewhere. But where? How can I get them? Conclusion Where does the class WantsToUseComponentB (which is NOT a Component and NOT instantiated by OSGI) get an instance of ComponentB from? Are there any patterns or best practises? As I said I managed to use a ServiceTracker in the Activator, but I thought that would be possible without it. What I am looking for is actually something like the BeanContainer of Springframework, where I can just say something like Container.getBean(ComponentA.BEAN_NAME). But I don't want to use Spring DS. I hope that was clear enough. Otherwise I can also post some source code to explain in more detail. Thanks Christoph UPDATED: Answer to Neil's comment: Thanks for clarifying this question against the original version, but I think you still need to state why the third class cannot be created via something like DS. Hmm don't know. Maybe there is a way but I would need to refactor my whole framework to be based on DS, so that there are no "new MyThirdClass(arg1, arg2)" statements anymore. Don't really know how to do that, but I read something about ComponentFactories in DS. So instead of doing a MyThirdClass object = new MyThirdClass(arg1, arg2); I might do a ComponentFactory myThirdClassFactory = myThirdClassServiceTracker.getService(); // returns a if (myThirdClassFactory != null){ MyThirdClass object = objectFactory.newInstance(); object.setArg1("arg1"); object.setArg2("arg2"); } else{ // here I can assume that some service of ComponentA or B went away so MyThirdClass Componenent cannot be created as there are missing dependencies? } At the time of writing I don't know exactly how to use the ComponentFactories but this is supposed to be some kind of pseudo code :) Thanks Christoph

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  • Has anybody use javafx on CDC J9?

    - by 4NDR01D3
    Is that possible?? I mean, I have an already working project that runs in windows mobile using the J9 virtual machine for CDC. My user interface there is using AWT and it works fine and it looks OK, but been honest it doesn't take real advantage of the devices were is running... So I start reading about JavaFX and that looks really cool, but all that I see about mobiles there is applied to CLDC, MIDP, etc. but my application is already running on CDC J9 and I can't change this cause I'm using a Derby database on it. So, my plan is to code the GUI again, but keeping the logic of the application. So do you guys think javafx is the way to go? or, am I wasting my time learning javafx for this project. Thanks in advance, Gustavo.

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  • how to convert byte array to key format??

    - by sebby_zml
    hi everyone, i would like to know how to convert byte array into key. i am doing an AES encryption/decryption. instead of generating a key, i would like to use my generated byte array. byte[] clientCK = Milenage.f3(sharedSecret16, RANDbytes, opc); let say i have a byte array called clientCK, stated above. i want to use it in AES encryption as shown below. Cipher c = Cipher.getInstance("AES"); c.init(Cipher.ENCRYPT_MODE, key); byte[] encValue = c.doFinal(valueToEnc.getBytes()); String encryptedValue = new BASE64Encoder().encode(encValue); therefore, i need to convert that byte array clientCK into key format. please help.

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  • What could I add to this code to allow the cell height to dynamically change as I edit the JTextArea

    - by Dr. Plaguey
    The derived classes I am using public class TextAreaRenderer extends JTextArea implements TableCellRenderer { public TextAreaRenderer() { setLineWrap(true); setWrapStyleWord(true); } public Component getTableCellRendererComponent(JTable jTable, Object obj, boolean isSelected, boolean hasFocus, int row, int column) { setText((String)obj); int height_wanted = (int)getPreferredSize().getHeight() + 10; if (height_wanted != rootJTable.getRowHeight(row)) rootJTable.setRowHeight(row, height_wanted); return this; } } class TextEditor extends AbstractCellEditor implements TableCellEditor { protected JTextArea ta; String txt; public TextEditor() { ta = new JTextArea(); } //Implement the one CellEditor method that AbstractCellEditor doesn't. public Object getCellEditorValue() { return ta.getText(); } // Implement the one method defined by TableCellEditor. public Component getTableCellEditorComponent(javax.swing.JTable table, Object value,boolean isSelected, int row, int column) { txt = value.toString(); ta.setText(txt); ta.setLineWrap(true); return new JScrollPane(ta); } public boolean isCellEditable(EventObject anEvent) { return true; } } Set column renderer and editor rootJTable.getColumnModel().getColumn(1).setCellRenderer(new TextAreaRenderer()); rootJTable.getColumnModel().getColumn(1).setCellEditor(new TextEditor());

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  • Checking if date parsing is correct

    - by Javi
    Hello, I have this code for checking whether the Date is OK or not, but it's not ckecking all the cases. For example when text="03/13/2009" as this date doesn't exist in the format "dd/MM/yyyy" it parses the date as 03/01/2010. Is there any way to change this behaviour and getting an exception when I try to parse a Date which is not correct? What's the best way to do this validation? public static final String DATE_PATTERN = "dd/MM/yyyy"; public static boolean isDate(String text){ SimpleDateFormat formatter = new SimpleDateFormat(DATE_PATTERN); ParsePosition position = new ParsePosition(0); formatter.parse(text, position); if(position.getIndex() != text.length()){ return false; }else{ return true; } } Thanks.

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