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  • java - useBean in jsp and getAttribute in jsp but NULL

    - by ravi parekh
    user is null in servlet. Pls let me if doing mistake. i m trying to get all html element in bean rateCode.jsp **<%@page import="com.hermes.data.RateCode_" %>** <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>Rate Code</title> </head> <body> **<jsp:useBean id="user" class="com.hermes.data.RateCode_" scope="session" > <jsp:setProperty name="user" property="*"/></jsp:useBean>** <form id="f_rateCode" action="/ratePromoCodes" method="post" > <table align="center" border="1" cellspacing="0"> <tr> <td colspan="2" align="center" class="header">Rate Code Administrations</td> </tr> <tr> <td align="right" style="border-style: solid;">Rate Code:</td> <td align="left" style="border-style: solid;"> <input type="text" id="code" name="code" value="${user.code}" size="10" maxlength="32" style="width: 100px"/> </td> </tr> <tr> <td align="right" style="border-style: solid;">Rate Description:</td> <td align="left" style="border-style: solid;"> <input type="text" id="description" name="description" value="<%=user.getDescription()%>" maxlength="128" size="40"></td> </tr> <tr><td><input type="submit" value="ok" /></td> </tr> </table> </form> Servlet - ratePromoCodes protected void doPost(HttpServletRequest req, HttpServletResponse resp) { RateCode rc = (RateCode) req.getAttribute("user"); Enumeration an = req.getAttributeNames(); Enumeration pn = req.getParameterNames(); Object o = null; while (an.hasMoreElements()) { o = an.nextElement(); System.out.println(o); } while (pn.hasMoreElements()) { o = pn.nextElement(); System.out.println(o); } } RateCode.java (javaBean) public class RateCode_ { private String code ; private String description; public String getCode() { return code; } public void setCode(String code) { this.code = code; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } }

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  • String length differs from Javascript to Java code

    - by François P.
    I've got a JSP page with a piece of Javascript validation code which limits to a certain amount of characters on submit. I'm using a <textarea> so I can't simply use a length attribute like in a <input type="text">. I use document.getElementById("text").value.length to get the string length. I'm running Firefox 3.0 on Windows (but I've tested this behavior with IE 6 also). The form gets submitted to a J2EE servlet. In my Java servlet the string length of the parameter is larger than 2000! I've noticed that this can easily be reproduced by adding carriage returns in the <textarea>. I've used Firebug to assert the length of the <textare> and it really is 2000 characters long. On the Java side though, the carriage returns get converted to UNIX style (\r\n, instead of \n), thus the string length differs! Am I missing something obvious here or what ? If not, how would you reliably (cross-platform / browser) make sure that the <textarea> is limited.

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  • Difficulty setting ArrayList to java.sql.Blob to save in DB using hibernate

    - by me_here
    I'm trying to save a java ArrayList in a database (H2) by setting it as a blob, for retrieval later. If this is a bad approach, please say - I haven't been able to find much information on this area. I have a column of type Blob in the database, and Hibernate maps to this with java.sql.Blob. The code I'm struggling with is: Drawings drawing = new Drawings(); try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = null; oos = new ObjectOutputStream(bos); oos.writeObject(plan.drawingPane21.pointList); byte[] buff = bos.toByteArray(); Blob drawingBlob = null; drawingBlob.setBytes(0, buff); drawing.setDrawingObject(drawingBlob); } catch (Exception e){ System.err.println(e); } The object I'm trying to save into a blob (plan.drawingPane21.pointList) is of type ArrayList<DrawingDot>, DrawingDot being a custom class implementing Serializable. My code is failing on the line drawingBlob.setBytes(0, buff); with a NullPointerException. Help appreciated.

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  • Embedded SQL in OO languages like Java

    - by Steve De Caux
    One of the things that annoys me working with SQL in OO languages is having to define SQL statements in strings. When I used to work on IBM mainframes, the languages used an SQL preprocessor to parse SQL statements out of the native code, so the statements could be written in cleartext SQL without the obfuscation of strings, for instance in Cobol there is a EXEC SQL .... END-EXEC syntax construct that allows pure SQL statements to be embedded in the Cobol code. <pure cobol code, including assignment of value to local variable HOSTVARIABLE> EXEC SQL SELECT COL_A, COL_B, COL_C INTO :COLA, :COLB, :COLC FROM TAB_A WHERE COL_D = :HOSTVARIABLE END_EXEC <more cobol code, variables COLA, COLB, COLC have been set> ...this makes the SQL statement really easy to read & check for errors. Between the EXEC SQL .... END-EXEC tokens there are no constraints on indentation, linebreaking etc., so you can format the SQL statement according to taste. Note that this example is for a single-row select, when a multiple-row resultset is expected, the coding is different (but still v. easy to read). So, taking Java as an example What made the "old COBOL" approach undesirable ? Not only SQL, but system calls could be made much more readable with that approach. Let's call it the embedded foreign language preprocessor approach. Would an embedded foreign language preprocessor for SQL be useful to implement ? Would you see a benefit in being able to write native SQL statements inside java code ? Edit I'm really asking if you think SQL in OO languages is a throwback, and if not then what could be done to make it better.

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  • Concurrency Problem in Java ...

    - by Tara Singh
    I am designing a client-server chat application in Java. This is a secure application where the messages are exchanged using cryptographic algorithms. I have one server and it can support many clients. My problem is that when one client logs on the server it works fine, but when another user logs into the system, the server starts giving me bad padding exceptions for the encrypted text. I am not able to figure out the problem, according to my logic, when new connection request to server is made, the server creates a thread for listening to the client. Is it possible that once the instance of thread class is created, it does all the processing correctly for the first client, but not for the second client because the variables in server listener thread class already have some previous value, and thus the encrypted text is not decrypted properly? Please advise how I can make this process more robust so that the number of clients does not affect how well the server functions.

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  • Static initializer in Java

    - by Szere Dyeri
    My question is about one particular usage of static keyword. It is possible to use static keyword to cover a code block within a class which does not belong to any function. For example following code compiles: public class Test { private static final int a; static { a = 5; doSomething(a); } private static int doSomething(int x) { return (x+5); } } If you remove the static keyword it complains because the variable a is final. However it is possible to remove both final and static keywords and make it compile. It is confusing for me in both ways. How am I supposed to have a code section that does not belong to any method? How is it possible to invoke it? In general, what is the purpose of this usage? Or better, where can I find documentation about this?

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  • Persisting Joda DateTime instead of Java Date in hibernate

    - by Tauren
    My entities currently contain java Date properties. I'm starting to use Joda Time for date manipulation and calculations quite frequently. This means that I'm constantly having to convert my Dates into Joda DateTime objects and back again. So I was wondering, is there any reason I shouldn't just change my entities to store Joda DateTime objects instead of Java Date objects? Please note that these entities are persisted via Hibernate. I found the jodatime-hibernate project, but I also was reading on the Joda mailing list that it wasn't compatible with newer versions of hibernate. And it seems like it isn't very well maintained. So I'm wondering if it would be best to just continue converting between Date and DateTime, or if it would be wise to start persisting DateTime objects. My concern is being reliant on a poorly maintained library. Edit: Note that one of my objectives is to be better able to store timezone information. Storing just a Date appears to save the date in the local timezone. As my application can be used globally, I need to know the timezone as well. Joda Time Hibernate seems to address this as well in the user guide.

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  • Spelling correction for data normalization in Java

    - by dareios
    I am looking for a Java library to do some initial spell checking / data normalization on user generated text content, imagine the interests entered in a Facebook profile. This text will be tokenized at some point (before or after spell correction, whatever works better) and some of it used as keys to search for (exact match). It would be nice to cut down misspellings and the like to produce more matches. It would be even better if the correction would perform well on tokens longer than just one word, e.g. "trinking coffee" would become "drinking coffee" and not "thinking coffee". I found the following Java libraries for doing spelling correction: JAZZY does not seem to be under active development. Also, the dictionary-distance based approach seems inadequate because of the use of non-standard language in social network profiles and multi-word tokens. APACHE LUCENE seems to have a statistical spell checker that should be much more suited. Question here would how to create a good dictionary? (We are not using Lucene otherwise, so there is no existing index.) Any suggestions are welcome!

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  • Java Logger with Servlets

    - by Sunny
    Hi Guys, I am using a wrapper class A which initializes the java.util.logger static class A { public static Logger logger; public static void init(){ logger = Logger.getLogger("test"); } Now, everywhere in my program I call A.init() and then logger.log("Message+uniqid"). But recently I moved to HTTP servlets and I am having problems. Basically, If a app is already running and the logger is logging... and someone else runs the app again, the logger from the previous instance stops and starts logging for the second one. Can anyone have a solution to how I should go about fixing this static variable issue? I can pass the logger into all constructor classes but thats really tedious. Any better solution would be appreciated..

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  • Java - AWT / Swing - handling the Event Descriptor Thread

    - by waitinforatrain
    Hi, I have a question about the 'Event Descriptor Thread'. I have a Main class that is also a JFrame. It initialises the rest of the components in the code, some of them do not involve Swing and some of them do. Is it enough to simply initialise the Main class using the EDT like this?... public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { new Main(); } }); } This way everything would run on the Event Dispatcher thread.

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  • java - call web service operation - wrong return type

    - by user1639680
    i have a simple web service with one method that returns List<org.company.data.mp> i've created a simple web service client and specified a web service with wsdl. in netbeans i try to call a web service operation: right click, insert code, ... and i pick my web service operation. the code gets inserted but the method's return type is not List<org.company.data.mp> but it is List<org.company.server.mp>! i don't get it.. in the package "server" there is no class called mp! i check the implementation class of my web service - it says the return type is ...data.mp not ...server.mp

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  • Using ServletOutputStream to write very large files in a Java servlet without memory issues

    - by Martin
    I am using IBM Websphere Application Server v6 and Java 1.4 and am trying to write large CSV files to the ServletOutputStream for a user to download. Files are ranging from a 50-750MB at the moment. The smaller files aren't causing too much of a problem but with the larger files it appears that it is being written into the heap which is then causing an OutOfMemory error and bringing down the entire server. These files can only be served out to authenticated users over https which is why I am serving them through a Servlet instead of just sticking them in Apache. The code I am using is (some fluff removed around this): resp.setHeader("Content-length", "" + fileLength); resp.setContentType("application/vnd.ms-excel"); resp.setHeader("Content-Disposition","attachment; filename=\"export.csv\""); FileInputStream inputStream = null; try { inputStream = new FileInputStream(path); byte[] buffer = new byte[1024]; int bytesRead = 0; do { bytesRead = inputStream.read(buffer, offset, buffer.length); resp.getOutputStream().write(buffer, 0, bytesRead); } while (bytesRead == buffer.length); resp.getOutputStream().flush(); } finally { if(inputStream != null) inputStream.close(); } The FileInputStream doesn't seem to be causing a problem as if I write to another file or just remove the write completly the memory usage doesn't appear to be a problem. What I am thinking is that the resp.getOutputStream().write is being stored in memory until the data can be sent through to the client. So the entire file might be read and stored in the resp.getOutputStream() causing my memory issues and crashing! I have tried Buffering these streams and also tried using Channels from java.nio, none of which seems to make any bit of difference to my memory issues. I have also flushed the outputstream once per iteration of the loop and after the loop, which didn't help.

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  • How does Java handle ArrayList refrerences and assignments?

    - by Jonathan
    Hey all- I mostly write in C but am using Java for this project. I want to know what Java is doing here under the hood. ArrayList<Integer> prevRow, currRow; currRow = new ArrayList<Integer>(); for(i =0; i < numRows; i++){ prevRow = currRow; currRow.clear(); currRow.addAll(aBunchOfItems); } Is the prevRow = currRow line copying the list or does prevRow now point to the same list as currRow? If prevRow points to the same list as currRow, I should create a new ArrayList instead of clearing.... private ArrayList<Integer> someFunction(ArrayList<Integer> l){ Collections.sort(l); return l; } main(){ ArrayList<Integer> list = new ArrayList<Integer>(Integer(3), Integer(2), Integer(1)); list = someFunction(list); //Option 1 someFunction(list); //Option 2 } In a similar question, do Option 1 and Option 2 do the same thing in the above code? Thanks- Jonathan

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  • Java Collections and Garbage Collector

    - by Anth0
    A little question regarding performance in a Java web app. Let's assume I have a List<Rubrique> listRubriques with ten Rubrique objects. A Rubrique contains one list of products (List<product> listProducts) and one list of clients (List<Client> listClients). What exactly happens in memory if I do this: listRubriques.clear(); listRubriques = null; My point of view would be that, since listRubriques is empty, all my objects previously referenced by this list (including listProducts and listClients) will be garbage collected pretty soon. But since Collection in Java are a little bit tricky and since I have quite performance issues with my app i'm asking the question :) edit : let's assume now that my Client object contains a List<Client>. Therefore, I have kind of a circular reference between my objects. What would happen then if my listRubrique is set to null? This time, my point of view would be that my Client objects will become "unreachable" and might create a memory leak?

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  • Java servlet and JSP accessing the same session bean

    - by Mykola Golubyev
    Let's say I have simple Login servlet that checks the passed name and creates User object and stores it in a session. User user = new User(); user.setId(name); request.getSession().setAttribute("user", user); response.sendRedirect("index.jsp"); In the index.jsp page I access the user object through jsp:useBean <jsp:useBean id="user" scope="session" class="package.name.User"/> <div class="panel"> Welcome ${user.id} </div> It works so far. The question: is this a valid usage or it is just current implementation uses the same name as the jsp bean id when stores and looks for a bean in a session?

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  • Java: Handling cookies when logging in with POST

    - by Cris Carter
    I'm having quite some trouble logging in to any site in Java. I'm using the default URLconnection POST request, but I'm unsure how to handle the cookies properly. I tried this guide: http://www.hccp.org/java-net-cookie-how-to.html But couldn't get it working. I've been trying basically for days now, and I really need help if anyone wants to help me. I'll probably be told that it's messy and that I should use a custom library meant for this stuff. I tried downloading one, but wasn't sure how to get it set up and working. I've been trying various things for hours now, and it just won't work. I'd rather do this with a standard URLconnection, but if anyone can help me get another library working that's better for this, that would be great, too. I would really appreciate if someone could post a working source that I could study. What I need is: POST login data to site - Get and store the cookie from the site - use cookie with next URLconnection requests to get logged-in version of the site. Can anyone help me with this? Would be EXTREMELY appreciated. It really does mean a lot. If anyone wants to actually help me out live, please leave an instant-messenger address. Thank you a lot for your time.

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  • Java - SwingWorker - Can we call one SwingWorker from other SwingWorker instead of EDT

    - by Yatendra Goel
    I have a SwingWorker as follows: public class MainWorker extends SwingWorker(Void, MyObject) { : : } I invoked the above Swing Worker from EDT: MainWorker mainWorker = new MainWorker(); mainWorker.execute(); Now, the mainWorker creates 10 instances of a MyTask class so that each instance will run on its own thread so as to complete the work faster. But the problem is I want to update the gui from time to time while the tasks are running. I know that if the task was executed by the mainWorker itself, I could have used publish() and process() methods to update the gui. But as the tasks are executed by threads different from the Swingworker thread, how can I update the gui from intermediate results generated by threads executing tasks.

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  • Enforcing a coding template in the getters of a class in java

    - by Yoav Schwartz
    Hello, I want to make sure all getters of the classes in a certain package follow a given template. For example, all getters must be of the form: XXX getYYY(){ classLock.lock(); return YYY; finally{ classLock.unlock(); } } Basically, I want that my project will not compile/run unless all getters are of that form. What is the best way to do that? I would prefer a solution that can be used as an Eclipse plugin. Thanks, Yoav

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  • JAVA vs .NET - Choice for way to go further [closed]

    - by Sarang
    I have my subject .Net acedemically. I also learned core Java and did a project as well. I took training from a Java firm. Now, as a skill I do have knowledge as both language. But, it is creating a large problem to me that, which field I should chhose? Even if having better OOP fundamentals, will it be easier for me to transfer from one to another in the future ? Please suggest me a way. Also, we do have may technologies available at both side, like JSP, JSF, J2ME, Share Point, SilverLight etc. Which is better as per their reliabity point of view? Which are fast growing and useful technologies used mostly in current IT corporate world ? Are they easier to learn at fresher's point of view? Please answer. Perhaps, this answer may help me mostly to create my way to learn them and go further. Every IT developer, please help to find me my way.

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  • Connection details & timeouts in a java web service client

    - by f1sh
    Hello fellow Coders, I have to implement a webservice client to a given WSDL file. I used the SDK's 'wsimport' tool to create Java classes from the WSDL as well as a class that wrap's the webservice's only method (enhanceAddress(auth, param, address)) into a simple java method. So far, so good. The webservice is functional and returning results correcty. The code looks like this: try { EnhancedAddressList uniservResponse = getWebservicePort().enhanceAddress(m_auth, m_param, uniservAddress); //Where the Port^ is the HTTP Soap 1.2 Endpoint }catch (Throwable e) { throw new AddressValidationException("Error during uniserv webservice request.", e); } The Problem now: I need to get Information about the connection and any error that might occur in order to populate various JMX values (such as COUNT_READ_TIMEOUT, COUNT_CONNECT_TIMEOUT, ...) Unfortunately, the method does not officially throw any Exceptions, so in order to get details about a ConnectException, i need to use getCause() on the ClientTransportException that will be thrown. Even worse: I tried to test the read timeout value, but there is none. I changed the service's location in the wsdl file to post the request to a php script that simply waits forever and does not return. Guess what: The web service client does not time out but waits forever as well (I killed the app after 30+ minutes of waiting). That is not an option for my application as i eventually run out of tcp connections if some of them get 'stuck'. The enhanceAddress(auth, param, address) method is not implemented but annotated with javax.jws.* Annotations, meaning that i cannot see/change/inspect the code that is actually executed. Do i have any option but to throw the whole wsimport/javax.jsw-stuff away and implement my own soap client?

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  • Documentation for java.util.concurrent.locks.ReentrantReadWriteLock

    - by Andrei Taptunov
    Disclaimer: I'm not very good at Java and just comparing read/writer locks between C# and Java to understand this topic better & decisions behind both implementations. There is JavaDoc about ReentrantReadWriteLock. It states the following about upgrade/downgrade for locks: Lock downgrading ... However, upgrading from a read lock to the write lock is not possible. It also has the following example that shows manual upgrade from read lock to write lock: // Here is a code sketch showing how to exploit reentrancy // to perform lock downgrading after updating a cache void processCachedData() { rwl.readLock().lock(); if (!cacheValid) { // upgrade lock manually #1: rwl.readLock().unlock(); // must unlock first to obtain writelock #2: rwl.writeLock().lock(); if (!cacheValid) { // recheck ... } ... } use(data); rwl.readLock().unlock(); Does it mean that actually the sample from above may not behave correctly in some cases - I mean there is no lock between lines #1 & #2 and underlying structure is exposed to changes from other threads. So it can not be considered as the correct way to upgrade the lock or do I miss something here?

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  • Java: repetition, overuse -- problem?

    - by HH
    I try to be as minimalist as possible. Repetition is a problem. I hate it. When is it really a problem? what is static-overuse? what is field-method overuse? what is class-overuse? are there more types of overuse? Problem A: when it is too much to use of static? private static class Data { private static String fileContent; private static SizeSequence lineMap; private static File fileThing; private static char type; private static boolean binary; private static String name; private static String path; } private static class Print { //<1st LINE, LEFT_SIDE, 2nd LINE, RIGHT_SIDE> private Integer[] printPositions=new Integer[4]; private static String fingerPrint; private static String formatPrint; } Problem B: when it is too much to get field data with private methods? public Stack<Integer> getPositions(){return positions;} public Integer[] getPrintPositions(){return printPositions;} private Stack<String> getPrintViews(){return printViews;} private Stack<String> getPrintViewsPerFile(){return printViewsPerFile;} public String getPrintView(){return printView;} public String getFingerPrint(){return fingerPrint;} public String getFormatPrint(){return formatPrint;} public String getFileContent(){return fileContent;} public SizeSequence getLineMap(){return lineMap;} public File getFile(){return fileThing;} public boolean getBinary(){return binary;} public char getType(){return type;} public String getPath(){return path;} public FileObject getData(){return fObj;} public String getSearchTerm(){return searchTerm;} Related interface overuse overuse of static in a Game

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  • Java File and ByteArray or InputStream - please quick help

    - by Peter Perhác
    I want to use jFuge to play some MIDI music in an applet. There's a class for the MIDI pattern - Pattern - and the only method to load the pattern is from a File. Now, I don't know how applets load files and what not, but I am using a framework (PulpCore) that makes loading assets a simple task. If I need to grab an asset from a ZIP catalogue, I can use the Assets class which provides get() and getAsStream() methods. get() returns the given asset as a ByteArray, the other as an InputStream. I need jFuge to load the pattern from either ByteArray or InputStream. In pseudo-code, I would like to do this: Pattern.load(new File(Assets.get("mymidifile.midi"))); however there is no File constructor that would take a ByteArray. Suggestions, please?

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  • How to create a rounded title border in Java Swing

    - by Stephane Grenier
    I do understand that to create a title border, you do something like: BorderFactory.createTitledBorder(" Your Title "); However this creates a rectangle border whereas I need a rectangle with curved corners. Now from what I understand you can create your own custom border by: class CustomBorder implements Border { ... } The problem is that I'm not sure how to write the code that overrides the method: public void paintBorder(Component component, Graphics g, int x, int y, int width, int height) Or better yet, is there a way to do it without implementing your own Border class? And if not, how would you write that custom Title Border? I'm ok with drawing a rectangle with rounded corners, but how do you do it so that there's space for the label too?

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  • Error while running jar file

    - by Manu
    Hi, I have created jar file which includes my .class , manifest file and dependency jar files like jar cfmv custadvicejar.jar mymanifest.txt Gchreportsautomation Bean Utils jxl.jar ojdbc14.jar where custadvicejar.jar - is my jar file name mymanifest.txt contains Main-Class: Gchreportsautomation.GCH_Home_Loan_Data_Cust_Advice_DAO "Gchreportsautomation" is the package name contains "GCH_Home_Loan_Data_Cust_Advice_DAO.class" [This class is my starting point of my application] Gchreportsautomation/ GCH_Home_Loan_Data_Cust_Advice_DAO.class "Bean" is the package name contains "GCH_Home_Loan_Data_Cust_Advice_Bean.class" Bean/ GCH_Home_Loan_Data_Cust_Advice_Bean.class "Utils" is the package name contains "Utils.class" Utils/ Utils.class and jxl.jar and ojdbc14.jar are jar files required for my application which i kept in parent directory of the .class files like D:\Excalcreation /Gchreportsautomation/ GCH_Home_Loan_Data_Cust_Advice_DAO.class /Bean/ GCH_Home_Loan_Data_Cust_Advice_Bean.class /Utils/ Utils.class /jxl.jar /ojdbc.jar while running the application i got error like Caused by: java.lang.ClassNotFoundException: jxl.format.CellFormat i know this is because of class-path error. how to rectify it. If i click my jar file ,the application has to run. please provide solution.

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