Applets and EJB's

Can an Applet work like a client for an EJB? How can I do this?
Thanks for all.

Yes you can use an applet here and applets can be very useful in a J2EE application. The rule of thumb should be to NOT use them unless your users demand a sophisticated UI component that can not easily be done in html/jsp/servlet. The advantages of an applet are the availability of swing and awt design ui objects. The major disadvantage is the requirement for users to download the swing and applet jars before they can run your app. If your doing an Amazon.com kind of thing that would be unacceptable but if your doing an intranet or industry specific site, it might be ok.
When you decide to use an applet you can just put in in a jsp. Create a servlet to handle talking to the applet and user http sockets to do so.
t3chi3

Similar Messages

Applets and EJBs

Hi:
we have a jDK 1.1.8 version Applet that needs direct access to a EJB 1.1 version ( Direct access i mean: No servlet in Between applet and EJB). The tool we are using to deploy the EJB to the Applicaton Server 3.6 ( Sybase) is PowerJ 3.6.1.
The Problem is the applet can access the EJB whenever we run the applet through Appletviewer BUT we get an Intial Context Failure error and subsequently everything related with the Bean functionality fails, when applet is run through a browser ( IE version 5.0 / 5.5 / 6.0)
Note: The applet's webserver and the Application server are on the same machine.
Can anyone help on this case.
Thank you.
Satish

Hi paul:
Thanks for your reply.
For ur question about using Applest.getCodeBase to construct the URL that you are using for your context provider,
We use the PowerJ tool to add the intial context and home interface of the EJB to the Applet application.
I am in a way restricted with this tool. The applet has been developed through this tool and the tool doesnot allow any manual changes to the Intial Context code and the Codebase that it generates.
I was going through many other forums , some say that Microsoft's ( IE / JVM ) doesnot support rmi stuff.
Do u think i should make sure that the applet has the rmi files in its classpath because when i look at the stacktrace of the applet , it gives
root execption: java.rmi.naming.* not found and subsequently Initial context fails.

Client Applet and EJB Server problem

Hi,
I developed a applet client that tries to connect to an EJB on the server side. The Applet runs okay in JDev3 but if I deploy it and test it outside the JDev tool I get an error. I tracked the problem to the following line of code:
ic = new InitialContext(environment);
Do I run into an applet security problem? If so what do i have to do to allow the applet to read/write to the local system?
Thanks for any hints!
Peter
Error I get
JAR cache enabled.
Opening http://pete/gateway/clientmanagement.jar no proxy
CacheHandler file name: C:\WINNT\Profiles\peter.000\Temporary Internet Files\Content.IE5\ALMN6PAZ\clientmanagement[1].jar
Creating an initial context
Opening http://pete/gateway/oracle/oas/container/nls/Version_en_US.class no proxy
CacheHandler file name: null
null

Hi,
I have still problems getting the client applet running. I tested it with the appletviewer and I modified the security.policy file. I allow the applet to almost everthing but i still get the following error:
What do I do wrong? Do I really have to sign the jar file? Do I miss some stub classes?
Thanks for any hints...
Peter
JAR cache disabled.
Opening http://pete/Gateway/. no proxy
Opening http://pete/Gateway/. no proxy
Opening http://pete/Gateway/test/Client.class no proxy
CacheHandler file name: C:\WINNT\Profiles\peter.000\Temporary Internet Files\Content.IE5\ALMN6PAZ\Client[1].class
Opening http://pete/Gateway/test/Client$1.class no proxy
CacheHandler file name: C:\WINNT\Profiles\peter.000\Temporary Internet Files\Content.IE5\ALMN6PAZ\Client$1[1].class
Creating an initial context
Looking for the EJB published as 'Gateway/GatewayProcessorRemote'
Opening http://pete:80/_RMProxyURL_ no proxy
Naming exception!
[Root exception is org.omg.CORBA.NO_IMPLEMENT: minor code: 0 completed: No]javax.naming.ServiceUnavailableException
at oracle.oas.jndi.oas.SecCosNamingContext.resolve(SecCosNamingContext.java:265)
at oracle.oas.jndi.oas.BeanContext.lookup(BeanContext.java:328)
at oracle.oas.jndi.oas.BeanInitialContext.resolve(BeanInitialContext.java:265)
at oracle.oas.jndi.oas.BeanContext.lookup(BeanContext.java:328)
at oracle.oas.jndi.oas.BeanInitialContext.lookup(BeanInitialContext.java:165)
at oracle.oas.jndi.oas.WrapperContext.lookup(WrapperContext.java:78)
at oracle.oas.jndi.oas.BeanContext.lookup(BeanContext.java:422)
at javax.naming.InitialContext.lookup(InitialContext.java:288)
at test.Client.initializeEJB(Client.java:104)
at test.Client.startButton_actionPerformed(Client.java, Compiled Code)
at test.Client$1.actionPerformed(Client.java:55)
at java.awt.Button.processActionEvent(Button.java:308)
at java.awt.Button.processEvent(Button.java:281)
at java.awt.Component.dispatchEventImpl(Component.java, Compiled Code)
at java.awt.Component.dispatchEvent(Component.java, Compiled Code)
at java.awt.EventQueue.dispatchEvent(EventQueue.java, Compiled Code)
at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java, Compiled Code)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:92)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:83)
null

Applet and EJB

Hi! there.
I use applet to get Bean from EJB.
when I lookup jndiName from context. I get following exception ,
java.lang.ClassCastException : weblogic.rmi.internal.StubInfo
How I can obtain EJBean from context in applets?
any reply is appreciated.
I use wlServer 6.1sp1, and I use java plugin1.3.1_01
I used following applet code
<html>
<OBJECT CODE = "Test.class" CODEBASE = "t3://localhost:7001/applets" ARCHIVE =
"weblogic.jar, micDcdpApprovalEJB.jar, micDcdpSystemEJB.jar" WIDTH = 500 HEIGHT
= 440>
</OBJECT>
</html>

Of course can.
You should call EJB remote interface.
This will help you
http://java.sun.com/j2ee/tutorial/1_3-fcs/doc/J2eeTutorialTOC.html

Applet calls EJB

Now I want to use an applet embeded in IE to call an EJB on the server.
They worked well in JBuilder6.0,and there are:
test.html
eb/*.class (the classes of EJB)
ebaptest/test.class (the class of applet)
Generated Source/*.class (some class made by JBuilder)
under the directory %JBuilderworkingdir%/classes.
But I want to deploy them to weblogic6.1,and how to do that.
I've tried many methods,and failed.
After I input "http://localhost:7001/test.html" in the IE,then the message "javax/ejb/EJBHome not found" is displayed.
pls help me,THX

Although I've used applets and EJBs together, through servlets, I've not done it directly.
I suspect that what is happening is that our applet, when deployed outside of the JBuilder environment, cannot find the j2ee.jar, which contains all of the javax.ejb.* classes and interfaces.
Make sure that this jar file is in your applet's codebase. That should fix it.
Paul

Using SWING and EJB

Had nebody used Swing for GUI and EJBs for business logic. HEre i need to use Swing for gui rather than JSPs.
Can nebody help??

My question is ...
How do u call EJBs from swing based applets..
In J2EE transaction management cud be done at server side but how will we manage with the swing app??

Applet and Struts

Hi all,
We have an existing application in struts and ejb.We have to add an applet to performa validation with the server.
things are fine but when the Action method is supposed to redirect for an action mapping the corresponding JSP isnot loading
so the flow should be something like Applet-->struts-->Jsp. But was unsuccesfull in redirect to JSP
I want the applet to send data and not to wait for response.
My applet codesnippet for sending data
                                String urlsuffix = host1.concat("/test.do?executeAction");
                    String url1 = getCodeBase().toString().concat(host1);
                    URL dataURL = new URL(new URL(url1),urlsuffix);
                    URLConnection con = dataURL.openConnection();
                    con.setDoInput(true);
                    con.setDoOutput(true);
                    con.setUseCaches(false);
                    con.setRequestProperty("Content-Type","application/x-java-serialized-object");
                    OutputStream outstream = con.getOutputStream();
                    ObjectOutputStream oos = new ObjectOutputStream(outstream);
                    oos.writeObject((Object)dbImages);
                    oos.flush();
                    oos.close();
                    System.out.println("Sent data...");
                    InputStream instr = con.getInputStream();
                    ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
                    Object temp = inputFromServlet.readObject();
                    String result = temp.toString().trim();
                    inputFromServlet.close();
                    instr.close();
                    System.out.println("response");
                    ....If i set con.setDoInput(true); to false then the applet fails to even send data.
Please let me know way forward.
Thanks
John

You're right, sorry.
Finally I think that the problem is more a Swing problem than a Struts problem.
It seems that there is a cache problem while using IE and appletContext.showDocument(URL url).
Is there someone of you that has successed in solving it ?

Diff b/w bc4j model and ejb model in adf11g

hi all,
iam murali iam new for adf 11g i have some dout's in adf11g ,can u please solve my probleam
what is the difference b/w bc4j componet and ejb componet,how to develop ejb application in adf11g.

,how to develop ejb application in adf11gTake a look at this tutorial for starters:
http://st-curriculum.oracle.com/obe/jdev/obe11jdev/ps1/ejb/ejb.html

Difference Between Applet and Swing

Difference Between Applet and Swing

The advantages and disadvantages of both applets and Swing are the small fluffy elephants you get inside of every box. They're quite well trained and can skeletonize your neighbors' annoying pets upon command.

IIS, Javascript, Signed Applet and ASP Blank Page Problem

Hi,
I'm having a problem using a Signed Applet in a site that runs in a IIS (Windows Server 2003).
My aspx web page uses the applet to read my smart card and get information from it.
This applet uses an auxiliar dll (stored in a second Signed Jar file) in order to read the information from my smart card.
The way the solution is design:
1) Aspx page is asked from server
2) Internet Explorer recieve the page and asks the server for it content (images, applet, javascripts, etc)
3) After this the JVM runs (console opens)
4) After the Aspx page render fully a javascript register onload fires and call an applet method
5) Applet receive the call and run the logic of the method:
     - reads the smart card;
     - calls Javascript function in order to fill aspx fields with information from smart card
     - calls Javascript function the simulates a click in a botton of aspx page (in order to call server side part sending data readed from smart card to server)
5) The server makes some logic with the information receive and responds to client registering in aspx page a call to another Javascrit function
6) The client received the asnwer from server and runs the Javascript function registered on step 5)
     This Javascript calls another method from applet and runs the following logic:
     - reads more information from smart card;
     - call javascript function in order to fill more fields of aspx page with the information readed
     - calls Javascript function the simulates a click in a botton of aspx page (in order to call server side part sending data readed from smart card to server)
7) The server makes some logic and call another pages with no Applets
8) Client asks for a second page with the same applet and we start with another logic express on steps 1);2);3),4);5) and then 7).
This is all ok, until sometimes the server stop responding correcly for requests regarding this two pages with the Applet.
When this happens the server just responds with a blank page.
     - with fiddler I can seer the request for the aspx page (that uses the applet)
     - but server responds with a blank html page
The JVM doesn't fire.
The IIS log don't show errors.
The eventviewer doesn't show errors.
The problem is solved with an IIS reset or a Application Pool reset.
After a while the problem returns.
This problem occours for other user in another machine, the server just stops responding correcly to request regarding pages with applets, the other pages still continue to work.
If we disable Java Control Panel->Advanced->Java Plug-in->Enable the next-generation Java Plug-in the problem seend to stop, but we can't force all clients to disable this option right?
Or there is a way to force the Applet to run with this option disabled?
As anyone experience similar problem?
Regards,
OF

This is all ok, until sometimes the server stop responding correcly for requests regarding this two pages with the Applet.
When this happens the server just responds with a blank page.
- with fiddler I can seer the request for the aspx page (that uses the applet)
- but server responds with a blank html pageWell, if http requests look identical in case of success and failure (pay attention to cookies, etc) then it has to be something on the server side.
It could be that server gets into this wrong state because of previous requests made by applet but it is hard to tell.
I am not clear how old/new plugin can make a difference unless your applets run in the legacy mode (i.e. you are actually trying to reuse SAME instance of the applet when
it is loaded next time).
I'd start with
1) carefully comparing good/bad sessions
2) checking whether server will serve correct response to another client when it serves "bad" page for current client
3) add debug statements to aspx - it is scripted page, may be some condition is not met and then it returns blank?
4) record all http requests in one session until you get to "error" state and then use any http server testing tool to "replay" this set of requests.
You should be able to get server into the same state without use of applet. Then you can try to tweak set of requests to see what makes a difference.

I need help with Applets and Multithreading

[hello all. first time poster. big fan of java.]
now to the important matter: Applets and Threads
=======================================
1) I have an applet with that implements the runnable interface, and has one thread (and a simple animation). If I try to view this applet in the applet viewer with JGrasp, it spits an insane error telling me
"java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)"
but, if I run the applet through a web browser, by putting it in an html document, it runs correctly, without error
What on earth is wrong, and how do I fix it?!?
2) I want to put 2 threads in my applet?
If I implement the Runnable interface, I can only have one Run() method in my applet, right?
So how do I define behaviour for 2 threads when I only have one run method in which to define the behaviour? Can I use two threads with the runnable interface, or do I have to make objects of my own defined thread classes?
3) I tried to make 2 threads in my applet by creating my own thread classes, and instantiating them in my applet (instead of implementing the runnable interface).
I still get the same insane error as I mentioned in my first point (which I expected), except now, the applet won't work even when viewed through a web browser!!
Please please help me. I am frustrated beyond belief (at what is probably a very simple problem)
I have searched and searched all over and found no answers on this

If I try to view this applet in the applet viewer with JGrasp, it spits an insane error telling me
"java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)"Don't know anything about JGrasp, but it runs with pretty tight security - thats what this insane error is all about. Use the appletviewer or a browser.
If I implement the Runnable interface, I can only have one Run() method in my applet, right?Correct
So how do I define behaviour for 2 threads when I only have one run method in which to define the behaviour?
Can I use two threads with the runnable interface, or do I have to make objects of my own defined thread classes?You can create two Runnable implementations (classes) in your applet.
example (missing code)
class MyApplet extends Applet {
void doSomething() {
void doSomethingElse() {
void startThreads() {
    Thread t = new Thread(new Runnable() { public void run() { doSomething();}});
    t.start();
    t = new Thread(new Runnable2());
    t.start();
class Runnable2 implements Runnable {
     public void run() {
       doSomethingElse();
}If the above seems confusing, read up on anonymous and inner classes.
3) I tried to make 2 threads in my applet by creating my own thread classesTry not subclassing thread - this causes a security check

Socket communication failure between Java applet and C++ application

I have a java applet that connects to a C++ application via Java's ServerSocket and Socket objects. THe C++ application is using the Winsock 2 API. The applet and application are running on an NT workstation (SP 6) and using IE (5.5) For a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close. Upon performing a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket. The Java applet can still receive messages from the C++ app but C++ cannot receive responses from the Java side. Java throws no exceptions and an explicit check of the socket shows no errors. Again, what puzzles me is that it works for simple C++ applications. Are there any known conflicts between Java and C++ in this regard?
I have inlcuded the basic java code segments below.
/ run Method.
* This method is called by the Thread.start() method. This
* method is required for the implementation of the Runnable interface
* This method sets up the server side socket communication and
* contiuously loops looking for requests from a external
* socket.
* @author Chris Duke
public void run(){
     // create socket connections
     boolean success = false;
     try {
         cServerSocket = new ServerSocket(cPortID);
         System.out.println("Waiting for client to connect...");
         cClientSocket = cServerSocket.accept();
         System.out.println("Client connected");
         // Create a stream to read from the client
         cInStream = new BufferedReader(new InputStreamReader(
           cClientSocket.getInputStream()));
         // Create a stream to write to the client
         cOutStream = new PrintWriter(
           cClientSocket.getOutputStream(), true);
         success = true;
     }catch (IOException e) {
         System.out.println("CommSocket:Run - Socket Exception(1) " + e);
         success = false;
     // if the socket was successfully created, keep the thread running
     while (success){
         try{
            // check socket to see if it is still available for reading
            if (cInStream != null && cInStream.ready()){
                // check for an incoming message
                String message = ReceiveMessage();
                // Send message to listeners
                Event(message);
            if (cInStream == null){
                success = false;
                System.out.println("CommSocket:Run - shutdown");
         }catch (IOException e){
            System.out.println("CommSocket:Run - Socket not ready exception");
            break;
// SendMessage method -
* Sends a text message to a connected listener through port specified by portID
* @author Chris Duke
* @param String message - This will be the message sent out through the server
* socket's port specified by portID.
   public void SendMessage(String message){
      cOutStream.println(message);
      if (cOutStream.checkError() == true)
        System.out.println("SendMessage : Flush = Error");
      else{
        System.out.println("SendMessage : Flush - No Error");
   }

a very simple C++ test applications the communictions work fine. Once more code gets added to the C++ application the portion of the socket that C++ listens to seems to close.
This quite strongly implicates the extra code in the C++ App. The firstly thing I would try would be telnet. Try connecting to both versions of the C++ Application and manually reproducing a proper exchange.
a recv call the return value is a zero. Microsoft insists this is a sign the Java side has shut down the socket.
A correct implementation of recv should return the number of bytes received, or -1 for an error. A zero return indicates no bytes received not a socket closed/error. This sounds like FUD to me.
Are there any known conflicts between Java and C++ in this regard?
I can see no obvious faults, though the code is incomplete, I don't think it's an sockets implementation issue, at either end, it sounds more likely to be a protocol/handshaking bug in the C++ App.

JDBC, JMS and EJB transactions - possible problem?

Hello,
          I am using Oracle 9, Weblogic 8.1 SP 4, MyEclipse and
          XDoclet.
          In my current project I have the following piece of code
          in one of my message driven beans (code cited as pseudocode
          without unnecessary details):
          * @ejb.bean name="MyMessageProcessor"
          * display-name="Display name for a MyMessageProcessor"
          * jndi-name="ejb/MyMessageProcessor"
          * description="Bean MyMessageProcessor"
          * destination-type="javax.jms.Queue"
          * transaction-type="Container"
          * acknowledge-mode="Auto-acknowledge"
          * subscription-durability="Durable"
          * generate="false"
          * @ejb.transaction type="Required"
          public class MyMessageProcessor implements MessageDrivenBean, MessageListener {
          public void onMessage(Message msg) {
               try {
                    //obtaining connections to two different databases via JNDi
                    java.sql.Connection connOne =
                    ((DataSource)ctx.lookup("DataSourceOne")).getConnection();
                    java.sql.Connection connTwo =
                         ((DataSource)ctx.lookup("DataSourceTwo")).getConnection();
                    // performing some UPDATEs and INSERTs on connOne and connTwo
                    // calling some other methods of this bean
                    //creating the reply JMS message and sending it to another JMS queue
                    Message msgTwo = this.createReplyMessage(msg)
                    this.queueSender.send(msgTwo);
                    //commiting everything
                    this.queueSession.commit();
               } catch (Exception ex) {
               try {
                    if (this.queueSession!=null) this.queueSession.rollback();
               } catch (JMSException JMSEx) {};
               this.context.setRollbackOnly();
          Some days ago (before the final remarks from my client) there used to be only one DataSource configurated on the basis of the
          connection pool with non-XA jdbc driver. Everything worked fine
          including the transactions (if anything wrong happend not only wasn't the replymessage sent, but also no changes were written
          to database and the incomming message was thrown back to the my bean's
          queue).
          When I deployed the second DataSource I was informed by an error message, that only one non-transactional resource may
          participate in a global transaction. When I changed both datasources
          to depend on underlying datasources with transatcional (XA) jdbc drivers, everything stopped working. Even if
          EJB transaction was theoretically successfully rolledbacked, the changed were written to the database
          and the JMS message wasn't resent to the JMS queue.
          So here are my questions:
               1. How to configure connection pools to work in such situations? What JDBC drivers should I choose?
               Are there any global server configurations, which may influence this situation?
               2. Which jdbc drivers should I choose so that the container was able to rollback the database transactions
               (of course, if necessary)?
               3. Are there any JMS Queue settings, which would disable the container to send message back to the
               queue in case of setRollbackOnly()? How should be the Queue configurated?
          As I am new to the topic and the deadline for the project seems to be too close I would be grateful
          for any help.
          This message was sent to EJB list and JDBC list.
          Sincerely yours,
          Marcin Zakidalski

Hi,
          I found these information extremely useful and helpful.
          The seperate transaction for sending messages was, of course, unintentional. Thanks a lot.
          Anyway, I still have some problems. I have made some changes to the
          code cited in my previous mail. These changes included changing QueueSessions
          to non-transactional. I also set the "Honorate global transactions" to true.
          I am using XA JDBC driver. After setting "Enable local transactions" to false
          (I did it, because I assume that JDBC transactions should be part on the global
          EJB transaction) I got the following error:
          java.sql.SQLException: SQL operations are not allowed with no global transaction by default for XA drivers. If the XA
          driver supports performing SQL operations with no global transaction, explicitly allow it by setting
          "SupportsLocalTransaction" JDBC connection pool property to true. In this case, also remember to complete the local
          transaction before using the connection again for global transaction, else a XAER_OUTSIDE XAException may result. To
          complete a local transaction, you can either set auto commit to true or call Connection.commit() or Connection.rollback().
          I have also inspected the calls of methods of bean inside of onMessage() method just to check, whether
          the transactions are correctly initialized (using the weblogic.transaction.Transaction class).
          My questions are as follows:
          1. Any suggestions how to solve it? I have gone through the google answers on that problem and only
          thing I managed to realize that JDBC must start its own transaction. Is there any way to prohibit it
          from doing that? Can using setAutocommit(true/false) change the situation for better?
          2. How to encourage the JDBC driver to be a part of EJB transaction?
          3. As I have noticed each of ejb method has its own transactions (transactions have different
          Xid). Each method of the bean has "required" transaction attribute. Shouldn't it work in such
          way that if already started transaction exists it is used by the called method?
          4. The DataSources are obtained in my application via JNDI and in the destination environment I will have slight
          impact on the configuration of WebLogic. What is least problematic and most common WebLogic configuration which would
          enable JDBC driver to participate in the EJB transaction? Is it the WebLogic configuration problem or can it be
          solved programmically?
          Currently my module works quite fine when "enable local transactions" for DataSources is set to true, but this way
          I am loosing the ability to perform all actions in one transaction.
          Any suggestions / hints are more than welcomed. This message was posted to jdbc list and ejb list.
          Marcin

Security issues with applets and windows Vista when printing to file

Hi, everyone
I am currently developing an application that prints out the result of some calculations.
from a Javascript file, the output finally ends up in a java applet that should print the file in a special printer.
For debugging purposes I have created a File printer that creates a file from the output comming to the printer; this way I can debug what commands the printer is receiving.
This worked well on Windows Xp; Vista always asks for permissions for the applet, and altough I guarantee these permissions, printer is not allowed to create the output file and reports an error writing
after a little research, I have found that java applets have all permissions when certificated as trusted applications; all but file creating permissions
anyone has any idea of how could I fix this problem?
Thanks in advance

HI,
Have you actually signed your applet? If the signers certificate is the trusted key store for Java it should treat your applet as trusted. You can use a self signed certificate for testing as long as the cert is in the trusted key store.
Some links that might help:
[http://java.sun.com/j2se/1.4.2/docs/tooldocs/windows/keytool.html]
[http://java.sun.com/j2se/1.4.2/docs/guide/plugin/developer_guide/rsa_signing.html]
Cheers,
Shane

I'm crazy!Applet and JNA Error:Library 'jnidispatch' was not found!

Hi all,
sorry to bother you, I really have no idea how to do JNA and Applet. I'm hardly mazy, man.
Every time it will throw an error to me :
Exception in thread "thread applet-JNAApplet-1" java.lang.UnsatisfiedLinkError: Library 'jnidispatch' was not found by class loader sun.plugin2.applet.JNLP2ClassLoader@291aff
     at com.sun.jna.Native.getWebStartLibraryPath(Native.java:858)
     at com.sun.jna.NativeLibrary.<clinit>(NativeLibrary.java:576)
     at com.sun.jna.Library$Handler.<init>(Library.java:140)
     at com.sun.jna.Native.loadLibrary(Native.java:372)
     at com.sun.jna.Native.loadLibrary(Native.java:357)
     at JNAApplet.init(JNAApplet.java:15)
     at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)My program is so easy, I just want use Applet to revoke JNA and use the JNA to load a native lib.
here is the structure of my program:
Applet code :
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JPanel;
import com.sun.jna.Native;
public class JNAApplet extends JApplet {
     public static Kernel32 kernel32 = null;
     @Override
     public void init() {
          createGUI();
          kernel32 = (Kernel32)Native.loadLibrary("Kernel32", Kernel32.class);
          if (kernel32 == null) {
               System.out.println("load kernel32 fail!");
          } else {
               System.out.println("load kernel32 success!");
     private void createGUI() {
          JPanel panelCenter = new JPanel();
          JButton butTest = new JButton("Test");
          panelCenter.add(butTest);
          setContentPane(panelCenter);
}When I run it on debug mode, it is ok! but when I deploy it , it will throw above error message to me.
My Applet html:
<html>
     <head>
          <title>JNA Applet</title>
     </head>
     <body>
     <script src="deployJava.js"></script>
    <script>
        var attributes = { code:'JNAApplet', width:300, height:300} ;
        var parameters = {jnlp_href: 'JNAApplet.jnlp'} ;
        deployJava.runApplet(attributes, parameters, '1.5');
    </script>
     </body>
</html>File 'JNAApplet.jnlp':
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0+" codebase="" href="">
    <information>
        <title>JNA Applet</title>
        <vendor>Steven</vendor>
    </information>
    <resources>
        <j2se version="1.5+"
              href="http://java.sun.com/products/autodl/j2se" />
        <jar href="JNAApplet.jar" main="true" />
    </resources>
    <applet-desc
         name="JNA Applet"
         main-class="JNAApplet"
         width="300"
         height="300">
     </applet-desc>
     <update check="background"/>
</jnlp>     I really have no idea. and I can't search any usefull infomation from Google and officer site.
Can any one help me? Thank you very much!!!!

Hi AndrewThompson64:
Did you mean the JNA project? Or are you refering to JNI, or ..something else?Yes, I mean is that I wanna jna.jar to replace JNI to code with Applet. I want Applet can run native library(.dll files).
That reads like so much nonsense to me.Sorry fo that.
Was there any 'caused by' part that you trimmed? I expected to see something to do with 'Security' or 'AccessControl'.Sorry, I can't saw any 'cause by' subsentence there. This message is just gain from Applet Console.(Is there any method to gain more message?)
About 'Security' and 'AccessControl' I just modify my java.policy file to allpermission. Subsequently, I signed all jar files.
For now I have 3 jar files(all have been signed ):
--example.jar : for this little program.(code include applet and application entry)
--jna.jar
--win32-x86.jar : include kernel32.dll and jnidispatch.dll for win32 and x86.
and 2 JNLP files:
--JNAApplet.jnlp the entry is JNAApplet.class (this jnlp does not work)
--JNAApp.jnlp     the entry is JNAApp.class (this jnlp works)
And for now new error message show like this:
Exception in thread "thread applet-JNAApplet-1" java.lang.UnsatisfiedLinkError: Library 'Kernel32' was not found by class loader sun.plugin2.applet.JNLP2ClassLoader@4aeb52
     at com.sun.jna.Native.getWebStartLibraryPath(Native.java:858)
     at com.sun.jna.NativeLibrary.loadLibrary(NativeLibrary.java:97)
     at com.sun.jna.NativeLibrary.getInstance(NativeLibrary.java:228)
     at com.sun.jna.Library$Handler.<init>(Library.java:140)
     at com.sun.jna.Native.loadLibrary(Native.java:372)
     at com.sun.jna.Native.loadLibrary(Native.java:357)
     at JNAApplet.init(JNAApplet.java:12)
     at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
Did you mean invoke?
Revoke: To annul by withdrawing.
Invoke: To call on.Yes, you got it. Thank you.
The JNLP file is invalid. ..I was about to put my 'standard' text here, but I'm sick of saying it. Search the forum for my posts - 50% of them, at least, mention validation and how to go about it.
Also, the applet-desc requires a documentbase.Thank you, I really think I have some invalid section. But I can't find it, and you said 'Search the forum for my posts - 50% of them...' , I can read the JNLP structure on site of sun and I can to read you post too(I'm doing like this).*I only want to know about how to load "native lib like *.dll" properly*.
What 'officer site'?I mean jna project site. Sorry for ambiguity.
Please fix that sticky '!' key. One '!' indicates astonishment, while two or more typically indicates a bozo. Thanks for your advice. Because I tried to find solution do my best lasting two days. I got nothing. I'm sadness.
here post my new files:
import javax.swing.JFrame;
import com.sun.jna.Native;
public class JNAApp {
     public static Kernel32 kernel32 = null;
     public static void main(String[] args) {
          // TODO Auto-generated method stub
          kernel32 = (Kernel32)Native.loadLibrary("Kernel32", Kernel32.class);
          JFrame frame = new JFrame();
          frame.setSize(500, 500);
          frame.setVisible(true);
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JPanel;
import com.sun.jna.Native;
public class JNAApplet extends JApplet {
     public static Kernel32 kernel32 = null;
     public void init() {
          createGUI();
               kernel32 = (Kernel32)Native.loadLibrary("Kernel32", Kernel32.class);
     private void createGUI() {
          JPanel panelCenter = new JPanel();
          JButton butTest = new JButton("Test");
          panelCenter.add(butTest);
          setContentPane(panelCenter);
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0+" codebase="" href="">
    <information>
        <title>JNA Applet</title>
        <vendor>Steven</vendor>
    </information>
    <resources>
        <j2se version="1.5+"
              href="http://java.sun.com/products/autodl/j2se" />
         <jar href="JNAApplet.jar" main="true"/>
         <jar href="jna.jar"/>
    </resources>
       <resources os="Windows" arch="x86">
         <nativelib href="win32-x86.jar"/>
         <nativelib href="kernel32.jar"/>
       </resources>
    <applet-desc
         documentBase=""
            name = "success"
         main-class="JNAApplet" width = "200" height = "200">
     </applet-desc>
     <update check="background"/>
       <security>
         <all-permissions/>
       </security>
</jnlp>
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0+" codebase="" href="">
    <information>
        <title>JNA Applet</title>
        <vendor>Steven</vendor>
    </information>
    <resources>
        <j2se version="1.5+"
              href="http://java.sun.com/products/autodl/j2se" />
         <jar href="JNAApplet.jar" main="true"/>
         <jar href="jna.jar"/>
    </resources>
       <resources os="Windows" arch="x86">
         <nativelib href="win32-x86.jar"/>
         <nativelib href="kernel32.jar"/>
       </resources>
    <application-desc
         main-class="JNAApp">
     </application-desc>
     <update check="background"/>
       <security>
         <all-permissions/>
       </security>
</jnlp>     Thanks & Best Regards,
Su Heng

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