java-programmer >>What is the difference between a BMP EntityBean and a DAO ?

What is the difference between a BMP EntityBean and a DAO ?

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  - Important and UrgentHi all,
    Please read on:
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  - TCP client application does detect network failureHi,
    
    This is a behavior of the TCP socket in Java I dont' understand:.
    Let say we have a simple client/server application running on TWO different
    machines.
    The client send bytes to the server.
    The server recieved the bytes and wait for about X sec.
    During this waiting time, we disconnect the server from the network (just by
    unplugging the server network cable).
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    SocketException is thrown : connection reset, because it is trying to send
    the response)
    But on the client side it is still stuck on a "rcv =
    commandInput.readLine();" statement (see after for the complete code), it
    will never be aware of the network failure !!! Even after one hour the
    client is still waiting to read something on closed socket. Is this the
    normal behavior ?
    
    In reality we are dealing with an application that use the FTP server to
    server mode (we are controlling only the command socket, the data transfer
    is made by the servers). We have to transfer huge file, thus we can not set
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    and it is not possible for us to detect the failure. The client will wait
    for ever the response.
    
    Does anybody have already deal with that ?
    
    Below is the simple client and server I made in order to make my experiment.
    The client just read the keyboard input and send it to the server; the
    server just echo the request except if the request
    is 'wait X', in this case it will wait for X sec before responding.
    
    Thanks by advance,
    
    Olivier MERIGON
    
    CLIENT:
    ----------------------------------------------------------------------------
    -------
    package com.iratensolutions.test.ftp;
    
    import java.io.BufferedReader;
    
    import java.io.IOException;
    
    import java.io.InputStreamReader;
    
    import java.io.OutputStreamWriter;
    
    import java.io.PrintWriter;
    
    import java.net.Socket;
    
    /**
    
    * A Client/Server application to test the network failure behavior with TCP.
    
    * This the client part. It just sends the keyboard input to the server.
    
    * @author Olivier MERIGON
    
    */
    
    public class TestNetworkFailureClient {
    
    public static void main(String[] args) {
    
    if (args.length != 1) {
    
    System.out.println("usage: java
    com.iratensolutions.test.ftp.TestNetworkFailureClient serverAdress");
    
    }
    
    Socket commandSocket = null;
    
    BufferedReader commandInput;
    
    BufferedReader keyboardInput;
    
    PrintWriter commandOutput;
    
    try {
    
    commandSocket = new Socket(args[0], 666);
    
    commandInput = new BufferedReader(new
    InputStreamReader(commandSocket.getInputStream()));
    
    keyboardInput = new BufferedReader(new InputStreamReader(System.in));
    
    commandOutput = new PrintWriter(new
    OutputStreamWriter(commandSocket.getOutputStream()));
    
    } catch (Exception e) {
    
    e.printStackTrace();
    
    return;
    
    }
    
    System.out.println("CLIENT STARTED");
    
    String snd;
    
    String rcv = null;
    
    try {
    
    do {
    
    System.out.print("KEYBOARD: ");
    
    snd = keyboardInput.readLine();
    
    if (snd != null) {
    
    commandOutput.println(snd);
    
    commandOutput.flush();
    
    System.out.println("SND: " + snd);
    
    rcv = commandInput.readLine();
    
    System.out.println("RCV: " + rcv);
    
    }
    
    } while (rcv != null);
    
    } catch (IOException e1) {
    
    e1.printStackTrace();
    
    }
    
    }
    
    }
    
    --------------------------------------------------------------------------
    
    SERVER
    
    ----------------------------------------------------------------------
    
    package com.iratensolutions.test.ftp;
    
    import java.io.DataInputStream;
    
    import java.io.IOException;
    
    import java.io.PrintStream;
    
    import java.net.ServerSocket;
    
    import java.net.Socket;
    
    /**
    
    * A Client/Server application to test the network failure behavior with TCP.
    
    * This the server part. The server can wait X second after responding to a
    request.
    
    * If a wait request is received, the server just answer the time waited
    after
    
    * the requested wait time, otherwise it respond immediatly the request
    number.
    
    * usage: wait intNbSec | any text
    
    * @author Olivier MERIGON
    
    */
    
    public class TestNetworkFailureServer {
    
    public static void main(String args[]) {
    
    ServerSocket echoServer = null;
    
    String line;
    
    DataInputStream is;
    
    PrintStream os;
    
    Socket clientSocket = null;
    
    try {
    
    echoServer = new ServerSocket(666);
    
    System.out.println("SERVER STARTED");
    
    } catch (IOException e) {
    
    System.out.println(e);
    
    }
    
    while (true) {
    
    try {
    
    clientSocket = echoServer.accept();
    
    System.out.println("Handling new client...");
    
    is = new DataInputStream(clientSocket.getInputStream());
    
    os = new PrintStream(clientSocket.getOutputStream());
    
    int loopId = 0;
    
    do {
    
    line = is.readLine();
    
    System.out.println("RCV: " + line);
    
    //Handle "Wait" command
    
    if (line.trim().startsWith("wait")) {
    
    String[] tab = line.split("\\s");
    
    boolean ok = false;
    
    try {
    
    int nbSec = Integer.parseInt(tab[1]);
    
    System.out.println("...waiting for " + nbSec + " sec.");
    
    try {
    
    Thread.sleep(nbSec * 1000);
    
    } catch (InterruptedException e1) {
    
    }
    
    String resp = "...end of wainting periode of " + nbSec + " sec.";
    
    os.println(resp);
    
    System.out.println("SND: " + resp);
    
    ok = true;
    
    } catch (Exception e) {
    
    ok = false;
    
    }
    
    if (!ok) {
    
    String resp = "usage: wait intNbSec | any text";
    
    os.println(resp);
    
    System.out.println("SND: " + resp);
    
    }
    
    //Handle "normal" action
    
    } else {
    
    os.println("# " + loopId);
    
    System.out.println("SND: # " + loopId);
    
    }
    
    loopId++;
    
    } while (line != null);
    
    } catch (IOException e) {
    
    System.out.println(e);
    
    }
    
    }
    
    }
    
    }
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    I'm building a j2ee Application on top of j2ee and JBoss 4.0.
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    to j2ee i have no idea how to realize this with j2ee and jboss.
    
    It would be great to get some ideas on how to solve this problem.
    
    greets from Germany
    
    Johannes Hermen
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  - .ear files in Sun Java StudioHi all,
    
    I am not sure if this is the right newsgroup for this question. But I just
    thought that some of you may be able to help me out; that's why I am asking
    you all this question.
    
    I have a .ear file and I just downloaded Sun Java Studio Enterprise 8. May
    I ask how can I import this .ear file in Sun Java Studio Enterprise 8? Can
    someone point me to the right direction?
    
    Thanks in advance,
    Monte
    
    --
    ---------------------------------------------
    "Whatever my lot, thou has taught me to say, 'it is well; it is well with my
    soul.'" -- Lyrics of It is well, it is well with my soul.
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    I want to transfer a block of XML between 2 DND objects in java
    
    What's the best way to do this?
    
    steve
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    2. If it does not exist where can I download it and where should I put it?
    3. If it exists then why doesn't this code run? I've even tried to register
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    thx.
    
    import java.sql.*;
    
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    Class.forName("oracle.jdbc.driver.OracleDriver");
    
    }
    
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    Have you a link about RequestInterceptor implementation in Tomcat?
    
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    public void run(){
    JPanel panel = new JPanel(); // create pane content object
    JLabel prompt = new JLabel("Processing log files");
    
    panel.add(prompt);
    
    Container contentPane = myFrame.getContentPane();
    contentPane.add(panel);
    
    myFrame.setTitle("Processing logs...Please Wait");
    myFrame.setBounds(100,100,350,75); // position frame
    myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    myFrame.toFront();
    panel.add(prompt);
    myFrame.setVisible(true);
    myFrame.pack();
    System.out.println ("pack1 done");
    myFrame.repaint();
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  - Xdoclet JBossHi all,
    
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    files to xdoclet embedded tags and ultimately generating deploy
    descriptors for JBoss.(4.0)
    
    My current application server is Pramati and i am migrating to
    JBoss(4.04GA) using xdoclet(1.2.3) as the EJB (Spec 2.0) deployment
    automation tool. I have the ejb.jar and other descriptors which are
    specific to Pramati Application server. I would like to generate the
    appropriate interfaces (Remote, Home etc) and JBoss specific
    descriptors for each EJB. I goggled but didnt find a complete example
    using xdoclet. The information seems to be scattered.
    
    I would like to know the steps for the following ( For eg I have a
    MyXYZBean.java )
    
    1) Adding appropriate xdoclet tags(Jboss specific) to this source file
    (MyXYZBean.java)
    2) Steps to generate the Remote, home etc interface source files ( Eg
    MyXYZRemote.java, MyXYZHome.java etc)
    3) Steps to generate JBoss specific descriptors (jboss.xml, ejb.jar
    etc)
    4) A task to be included in my build.xml which takes care of steps 1) ,
    2) and 3) appropriately.
    
    Many thanks,
    Santosh
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    Until now the JAAS config file was in a folder (conf/) and the
    application just ran fine.
    To prepare for the deployment of the application with Webstart I packed
    the folder with the config file in the application's JAR. Now JAAS
    can't seem to find the file anymore.
    
    Working:
    
    |--application.jar
    |--conf/
    |--auth.conf
    
    Failing:
    
    |--application.jar
    |--conf/
    |--auth.conf
    
    Both have the same manifest:
    
    Manifest-Version: 1.0
    Ant-Version: Apache Ant 1.6.5
    Created-By: 1.5.0_04-b05 (Sun Microsystems Inc.)
    Main-Class: com.fpc.nokeos.core.client.launch.Launcher
    Class-Path: . conf
    
    I also tried expliciitely adding "conf/auth.conf" to manifest but it
    didn't work either.
    
    The stacktrace I get is
    
    08:57:42,250 - ERROR: [NokeosClientSecurity] Could not connect to the
    server.
    Please check your network connection.
    java.lang.SecurityException: conf/auth.conf (No such file or directory)
    at
    com.sun.security.auth.login.ConfigFile.<init>(ConfigFile.java:97)
    at
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    at java.lang.Class.newInstance0(Class.java:350)
    at java.lang.Class.newInstance(Class.java:303)
    at
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    at java.security.AccessController.doPrivileged(Native Method)
    at
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    at
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    at
    com.fpc.nokeos.core.client.launch.Launcher.main(Launcher.java:66)
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    directory)
    at
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    at
    com.sun.security.auth.login.ConfigFile.<init>(ConfigFile.java:95)
    ... 16 more
    
    How can I make it work?
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    Content-Type: text/plain
    Content-Transfer-Encoding: 7bit
    
    Hi there,
    
    I've been looking at the JLint port (java/jlint). This port is flagged
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    at it, comment it and check it in if you like.
    
    Best regards, Roman
    
    --=-hJb57ejBSXdHWUZd6IhV
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    To unsubscribe, send any mail to "email***@***.com"
    
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- 13
  - EJB: removing local TOsHi!
    
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    I have a Collection of Local objects which I want to remove(). So I thought
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    So, I iterate thru the Collection and call remove() on each Local object.
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    The only solution seems to iterate over the collection, put the objects to
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    Well, there must be something I misunderstood about EJB, right?

Author

Message

LarsWill

Posted: 2004-10-16 18:15:00

Top

java-programmer, What is the difference between a BMP EntityBean and a DAO ? As I read in a couple of articles a BMP (Bean Managed Persistence is an EntityBean
where the programmer has to care about the SQL statements.
On the other side a DAO implements the direct access to an SQL database.

But isn't that the same?
What are the differences ?

Lars

Michael Borgwardt

Posted: 2004-10-17 2:37:00

Top

java-programmer >> What is the difference between a BMP EntityBean and a DAO ? Lars Willich wrote:

> As I read in a couple of articles a BMP (Bean Managed Persistence is an EntityBean
> where the programmer has to care about the SQL statements.
> On the other side a DAO implements the direct access to an SQL database.

Actually, neither necessarily uses SQL, though it's of course the most
common case.

> But isn't that the same?
> What are the differences ?

IMO the main difference is that a DAO isn't necessarily an EJB. i.e.
Entity Beans that use BMP are a special kind of DAO.

Paul & Neelam Checknita

Posted: 2004-10-17 12:32:00

Top

java-programmer >> What is the difference between a BMP EntityBean and a DAO ? You're not really comparing the like with the like. A DataAccessObject is a
core J2EE pattern -- among other things, it abstracts potentially
vendor-specific calls to a database from business objects. A
DataAccessObject could be utilized with something like BMP. A BMP
EntityBean is an entity object that manages its own persistence. Which
means that the bean implements its own persistence by including
JDBC/SQLJ/etc right in the entity bean methods.

See the following article, which explains it in further detail,
http://java.sun.com/blueprints/corej2eepatterns/Patterns/DataAccessObject.html

NC

"Lars Willich" <email***@***.com> wrote in message
news:ckqsbm$ulg$04$email***@***.com...
> As I read in a couple of articles a BMP (Bean Managed Persistence is an
EntityBean
> where the programmer has to care about the SQL statements.
> On the other side a DAO implements the direct access to an SQL database.
>
> But isn't that the same?
> What are the differences ?
>
> Lars
>

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    thread which connections to close?
- 8
  - How does one combine the Adapter and Factory design patterns in a memory efficient way?I'm using the adapter pattern, and I've got a factory to generate adapters
    for passed in adaptees. Let's call the class of the objects getting adapted
    "Foo", and the Adapter class itself "Bar".
    
    So here are some details specific to my situation:
    
    1) the constructor for Bar is private and visible to the factory (Bar is
    acting as its own factory), so I can completely control when and how Bar
    gets instantiated.
    2) If an existing adapter for a given instance of Foo doesn't exist yet,
    I'll want to create a new Bar which matches with it.
    3) If there already is a adapter h for Foo, I have to return that existing
    match, and NOT generate a new one.
    4) upon a request for an adapter for null, I return null.
    
    This is relatively easy to do if I have infinite memory. I just create a
    Map<Foo,Bar>, like so:
    
    <code>
    public class Bar {
    private final Foo f;
    
    private Bar(Foo f) {
    this.f = f;
    }
    
    private final static Map<Foo,Bar> mapping = new
    ConcurrentHashMap<Foo,Bar>();
    
    public static Bar make(Foo f) {
    if (impl == null) {
    return null;
    }
    synchronized (mapping) {
    if (!mapping.containsKey(f)) {
    mapping.put(f, new Bar(f));
    }
    Bar b = mapping.get(f);
    assert returnValue != null;
    return returnValue;
    }
    }
    
    public void newInterfaceWhichModifiesState() {
    this.f.oldInterfaceWhichModifiesState();
    }
    
    public int newInterfaceWhichGetsState() {
    return this.f.oldInterfaceWhichGetsState();
    }
    }
    </code>
    
    However, it's possible that the calling code is generating billions and
    billions of instances of Foo, and then throwing them away after their first
    use. My Map would prevent the garbage collector from being able to reclaim
    those instances. I can safely delete those "throwaway Foos" and their
    matches from my Map, because if there doesn't exist a reference to some
    instance of Foo anywhere else in the JVM, then it can't possibly ever occur
    that that instance will ever get passed into my make(Foo) method, in which
    case, I would never need to return its corresponding Bar.
    
    The two potential-solutions I looked at, Maps of WeakReferences and
    WeakHashMap, turned out not to satisfy my requirements.
    
    If instead of a Map<Foo,Bar>, I had a Map<Foo,WeakReference<Bar>>, then it's
    possible that the matching Bar would get garbage collected, but the instance
    of Foo would get passed in again, and there's no way for me to recover its
    matching pair, thus violating condition (3) mentioned above.
    
    If I replace Map<Foo,Bar> with WeakHashMap<Foo,Bar>, none of the keys will
    get GCed, because instances of Bar contain a strong reference to Foo, via
    the private field f. If I change that field to a weak reference, then it's
    possible the instance of Foo that's being adapted will get GCed while the
    corresponding adapter is still in use, resulting in the newInterface()
    method failing.
    
    I think what I need is some sort of special PairOfWeakReference class such
    that if there are any references to either an instance of Foo or its
    corresponding Bar, then BOTH remain uncollectable. However, once there do
    not exist any strong references to either instances, then the pair become
    collectable simultaneously.
    
    Using a pair class, as in:
    
    <code>
    public class Pair<A,B> {
    public final A a;
    public final B b;
    
    public Pair(A a, B b) {
    this.a = a;
    this.b = b;
    }
    }
    </code>
    
    WeakReference<Pair<Foo,Bar>> won't work either, because the WeakReference
    class is checking against references to instances of the Pair class, rather
    than references to the instances of Foo and Bar.
    
    This adapter-factory combination doesn't sound like something that unusual
    or obscure, so I figure I must be missing something simple from effectively
    implementing it. Can anyone tell me what that is?
    
    - Oliver
- 9
  - showdocument() problem (or bug?)I have a trusted applet that is supposed to generate a pdf file and
    save it as a temporary file on the local machine, then display it.
    Since display of such an animal can only happen with showDocument(URL,
    type) I am trying to build the url using :
    URL url = new URL("file:" + File.separator + File.separator +
    "filename.pdf");
    
    and this does indeed work IFF I run the applet locally. However, if the
    bloody thing is running connected to the server, it does not. Then the
    only command that works is
    URL url = new URL(getCodeBase(), "filename.pdf");
    so I had to bytestream the pdf down to server, have it install it in a
    file and make the call. A real waste, considering I'm supposed to be
    writing non-polluting software. Any ideas as to what's wrong with this?
    Thanks.
- 10
  - JTable refresh problemI have a JTable where I paint some of the cell backgrounds with
    a custom renderer. getTableCellRendererComponent() paints with
    drawLine() and fillRect() and that sort of thing. It's all working
    fine but when I drag another window over the JTable, or when I
    scroll it, sometimes it's not getting repainted correctly.
    Any ideas how to make it refresh or repaint itself at the right
    times?
    
    I looked in the group archives and there were a lot of other messages
    but they were about when a table's content changes dynamically.
    I'm not changing the content, I'm just trying to get the table
    to keep the correct content when scrolled and when other windows
    pass over it.
    
    Thanks in advance,
    
    - Mitch Gart
- 11
  - JFace getting startedHi
    
    I try to run a simple SWT/Jface example. I am running this from inside
    eclipse 3.2.0 and I have included the following in my classpath:
    swt.jar - Taken from swt-3.3M3-win32-win32-x86.zip
    jface.jar - Taken from program files\eclipse\plugins and Renamed from
    
    org.eclipse.jface_3.2.0.I20060605-1400.jar
    
    Here is the class:
    
    import org.eclipse.jface.window.*;
    import org.eclipse.swt.widgets.*;
    
    public class MyJFaceExample1 extends Window {
    
    public MyJFaceExample1() {
    // super(null); //Wont compile with null as the beginner example says
    it should
    super(new Shell()); //Compiles
    }
    
    public static void main(String[] args) {
    MyJFaceExample1 demo = new MyJFaceExample1();
    demo.setBlockOnOpen(true);
    demo.open();
    Display.getCurrent().dispose();
    }
    
    ------------------------------------------------------------
    
    This compiles fine but when I try to run this I get:
    java.lang.NoClassDefFoundError:
    org/eclipse/core/commands/common/EventManager
    
    I then copy c:\program
    files\eclipse\plugins\org.eclipse.core.commands_3.2.0.I20060605-1400.jar
    and rename it to core.jar.
    
    I then get the following error: java.lang.NoClassDefFoundError:
    org/eclipse/core/runtime/ListenerList
    
    Then I am stuck.
    
    Please help me with getting started with JFace.
- 12
  - Java (SE6) documentation in info formatHi,
    
    is it possible to download uptodate Java documentation in .info
    file(s)?
    
    Thanks,
    P
- 13
  - Non-text based source code. I don't have much to add above what's said at the blog entry, so I'll
    just link to it:
    http://www.realityinteractive.com/rgrzywinski/archives/cat_ideas.html
    
    It's not a particularly novel idea (Roedy has mentioned it often in this
    newsgroup, for example; calls it "SCID" I believe), but it's interesting
    because (assuming those screenshots weren't doctored), it looks like we'll
    be seeing IDEs with practical support for non-text based source code in the
    near future (on the order of single-digit years?)
    
    - Oliver
- 14
  - &# in PARAM NAME causing problemsHello,
    
    I have an application that generates a HTML document that contains an
    applet. It places raw data into the PARAM NAME tag. Well, once in a blue
    moon it places the numeric character reference &# into the data. When my
    Java applet imports this using the getParameter command, it reacts
    differently between different version of IE. One solution is to not let my
    original application generate the sequence &#, however, this does not fix
    the HTML documents that have already been generated in the past. It would be
    nice to just fix the Java applet so it can import this raw data without
    having to recognize &# as a numeric character reference.
    
    Is this possible?
    
    Here is my HTML code:
    
    <CENTER><APPLET CODE="graphics.class" ALIGN=RIGHT HEIGHT=420 WIDTH=220>
    <PARAM NAME=Graphics VALUE="
    >=>.>/(%<!<!>((6<0>%(#(!(+>%(!(>(!>%(%>%>!(&/<(*<&>*/6>0>((!>+(%(<()<&(!>!(=(><!>#/)(#(6>+/=(.>+/1>&>#16<!/>(*(#/!(*(!/!(//#((>=1(/=/01)(/1=/!(=1//61!!6/>!61=>1!>/+!(!./!!+1%//./1*1<.&//./%.1!.+%*..<#&.%/.%%1.1/.&//.*.>1=!01*1=!!(.!1!<(&!)/*/(1#(+1+1!/)1!<!(11>>./#1)(>/%/*(//!>%/#/#((1<(/(616(&/)/<>#>.(%(1(+(<(+>1>+(>(%>&(+>((0(%((((>+(0(6>>()(/>+(&>%<%>.(6>#>>(!<.()(%<!>((!>!<&(!()<!(=(<>/>1<#??
    "></APPLET></CENTER>
- 15
  - dynamic instanciation of a generic classHi,
    
    I've a question about Tiger (Java 5), genercity and dynamic instanciation
    of class.
    
    I can't found tutorial or sample via the Net.
    
    By exemple :
    
    public class A<T>
    {
    private T v;
    
    public A(T v)
    {
    this.v=v;
    }
    
    public void test()
    {
    System.out.println(v.getClass().getName());
    }
    }
    
    I'd like instanciate the A class with something like that : Class.forName
    ("A").... but why can I specified T parameter ?
    
    Please, send me some sample or URL.
    
    Thanks,
    Arnaud.