JDBC and Applet communication

HI!
I am not able to connect my Oracle datbase in Applet.
Please give ur suggestions.
Thanx in Adv
Vink

Hi
An applet can request a socket connection only to the server from which it is downloaded from.
If your database and the webserver are running on different hosts then the applet security model restricts the applet from connecting to the database. You need to set the proper security policies and sign the applets.
Refer the following link on applets
http://developer.java.sun.com/developer/technicalArticles/Security/Signed/
Also post the complete error/stack traces if you get into some problems.
Hope this helps
shrini

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Cann't access oracle 9i with thin jdbc and applet

Hi..
I write thin jdbc applet and application programs..
application programs works well..
but applet cann't connect...
error messages below..
access denied (java.util.PropertyPermission oracle.jserver.version read)
web server and dbms server are on same machine...
applet programs is in the demo applet program of oracle's installation folders...
I hope your comment...
thanks..

Hi Hyun,
This is basically just a guess -- since you didn't provide a lot of information (in my opinion) -- but I assume that "oracle.jserver.version" is some "System" property.
Due to the security restrictions placed on an applet (and which aren't imposed on an application), an applet cannot access all of the "System" properties -- only some of them (like "java.version", for example). So that's why (I think) your application works, but your applet doesn't.
There are several workarounds for overcoming an applet's security restrictions -- the most popular (as far as I know) is to "sign" your applet. There are many Internet resources available that explain how to "sign" an applet -- a simple Internet search will be more than enough to get you going (if that's at all relevant to your situation).
Hope this has helped you.
Good Luck,
Avi.

Policies, JDBC and applets

I have looked all over the WWW for info on this and have found loads of questions but not one clear cut answer. It's amazing the number of "OK, thanks, I got it working" without saying how. Here is my problem. I have a JDBC applet, running on IE. If I run it locally it works like a champ. If I run it through "localhost:xxx.html I get that infamous "Unable to connect to MySQL on localhost:3306, are you sure it's running..Java.security.accesscontrol exception. One problem mentioned setting a policy..didn't mention which one though. So I set socket connection priv on localhost:3306 as that was explicitly mentioned in the exception. Seemed like a good idea. It was but still did not solve the problem. So what I think would be really swell is if in one place there was a really good answer on how to set up an applet using JDBC under IE to work with respect to the security manager. Could someone please help?
Thanks in Advance,
Walt

Hi,
Let's first c an example of the intended functions of the two methods.
We have an HTML-type document, "document.html" at:
host_name/some_directory/document.html
and we have our applet, "OurApplet.class" at:
host_name/some_directory/applets/OurApplet.class
In the "document.html", we have embedded "OurApplet.class" inside. Then getDocumentBase().toString() should supposedly be:
host_name/some_directory/document.html
and getCodeBase().toString() should supposedly be:
host_name/some_directory/applets/OurApplet.class
If the directories containing the HTML document and the applet were the same, both methods would give the same thing; if they r not, it'd be like the above.
Ok, the above is the way they'r intended to be. According to the bug ChuckBing has shown us (actually the methods r under the class java.applet.Applet instead of under the package java.applet), the two methods however produce what their counterpart friends is supposed to produce. So if your version of SDK/JRE produces the bugged version of the output, u can replace the method with its counterpart friend. However, keep in mind of the target JRE the applet will be run on and the possibility of more than one potential audience JREs.

Jdbc and applet

I have Jdbc code which is running fine as a stand alone program. When i integrated it with an apllet it gives me
access denied (java.lang.RuntimePermission accessClassInPackage.sun.jdbc.odbc)
I m using netbeans. 3.6 The intersting thing is the code runs when I debug it But gives the above error when i execute it. I hope some one can help me out. It is urgent

You should urgently read this:
http://java.sun.com/docs/books/tutorial/applet/overview/security.html

JDBC and Applets

I'm trying to view results of a query in an applet.
Keep getting the error
ClassNotFoundException: sun.jdbc.odbc.JdbcOdbcDriver
I know there is security issues. can i get around them???
This application runs perfect in a driver program...
can anyone help??????
Thanks

I set the policy tool but it still returning "ClassNotFoundException"
Could you check my code to see if there is anything wrong???
     String url = "jdbc:odbc:timetable";
     String query = "select Day, Room from Thirdyear";
     try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();
     } catch(Exception ex) {
     text.appendText("My Error: \n" + ex);
text.appendText("\n" + ex);
System.out.println(ex);
     // return;
     try {
     Connection con = DriverManager.getConnection(url, "", "");
     Statement stmt = con.createStatement();
     ResultSet rs = stmt.executeQuery(query);

Regarding communication between JSF and applet.

Hi all,
I have to send a array of int value from JSF to the applet method and vice versa,
so how can I do that?
Is there any straight forward way is there?
Or I need to use javascript in between applet and JSF for communicating.
If this is case can give some links so that I can go through it.
What I need is, I have jsf table(grid) when I select a row from table, for the selected row I have to display selected row ID in applet and vice versa.
Any suggestion or links will be appreciated, thanks in advance.
Thanks
daya

thanks and sorry for late reply, let me go through the link,
i have tried with JavaScript, i got stuck, i need to call a JavaScript method for JSF component event listener. I searched in Google but no help regarding same.
Actually what I need is, I have JSF Component i.e. GridView(Table) and applet in a page. And for each row selection in GridView(table) I need to call a javascript method (with column value), and vice versa.
Can you give suggestion or any link so that can proceed further.
and i am able to communicate between applet which are included in the page
Thanks
Daya

Servlet/Applet communication, data limit?

I have an applet that uses a servlet as a proxy to load/retrieve images from an Oracle database. I have a problem when trying to retrieve images larger than 9-10kb from the database. When using JDBC from a Java Application I don't have any probelms but through the Applet-Servlet configuration I do.
I use the following code in the Applet:
URL url =new URL("http","myserver",myport,"/servlet/MyServlet");
HttpURLConnection imageServletConn = (HttpURLConnection)url.openConnection();
imageServletConn.setDoInput(true);
          imageServletConn.setDoOutput(true);
          imageServletConn.setUseCaches(false);
imageServletConn.setDefaultUseCaches (false);
imageServletConn.setRequestMethod("GET");
byte buf[] = new byte[imageServletConn.getContentLength()];
BufferedInputStream instr = new BufferedInputStream(imageServletConn.getInputStream());
instr.read(buf);
Image image = Toolkit.getDefaultToolkit().createImage(buf);
// then code to display the image
And the following for the Servlet:
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("image/gif");
byte[] buff = loadImage(); // this method returns a byte array representing the image.
response.setContentLength(contentLength);//contentLength is the size of the image
OutputStream os = response.getOutputStream();
os.write(buff);
os.close();
thanks in advance!

thanks for your replay,
I tried your suggestion but whatever I do it seems that tha applet only brings the first 5-10k of the image from the servlet. This is the value I get from instr.read() or any other type of read method. The value of bytes is not always the same.
Now I also have something new. For images greater than 100k or so I get this error:
java.io.IOException: Broken pipe
     at java.net.SocketOutputStream.socketWrite(Native Method)
     at java.net.SocketOutputStream.socketWrite(Compiled Code)
     at java.net.SocketOutputStream.write(Compiled Code)
     at java.io.BufferedOutputStream.write(Compiled Code)
     at org.apache.jserv.JServConnection$JServOutputStream.write(Compiled Code)
     at java.io.BufferedOutputStream.write(Compiled Code)
     at java.io.FilterOutputStream.write(Compiled Code)
     at interorient.DBProxyServlet.doGet(Compiled Code)
     at javax.servlet.http.HttpServlet.service(Compiled Code)
     at javax.servlet.http.HttpServlet.service(Compiled Code)
     at org.apache.jserv.JServConnection.processRequest(Compiled Code)
     at org.apache.jserv.JServConnection.run(Compiled Code)
     at java.lang.Thread.run(Compiled Code)
I am using the Oracle Internet application server (ias 9i) which actualy uses the apache web listener.
It seems that this servlet-applet communication is really unstable. If you have anything that may help me it will be greatly appriciated. You can even e-mail me at [email protected]
thanks!

Jar files and applet

My applet class is using other classes in my package,
So do i need to create a jar file and specify that jar file in <applet archieve = :myjar.jar"
I did created the jar file , but its not loading up, the browser just says Loading java applet, what might be the reason, does it depends on size of jar file?
or my tags are wrong.
my applet tag is
<html>
<applet archive = "myjar.jar"
code = "front.class"
width.. >
the front.class file is also in myjar.jar.
Any help....
Also one more question,
Can i call other applets within one applet class.
I have a gui, when a particular button is clicked on applet
i want to go to other applet, so how should i call it in that buttons action listner?
And in my applet class i am using one other class from my package which actually coonects to databse through JDBC. now say i have a button on my applet whihc says "Connect", and when that button is clicked then I created object of my other class which makes connection
through databse. So will this work from applet?
Thanks

You didn't show all of your applet tag, but it should look like this:
<HTML>
<APPLET CODE = front.class, ARCHIVE = myjar.jar, width = ???, height = ???>
</APPLET>
</HTML>
Assuming your applet is not crashing, this should load it. I recommend using the appletviewer tool in the JDK, it provides more detailed error messages. I hope this works for you.
Now inter-applet communication. This is forbidden, sorry. However, if you really want to get fancy; remember that all applets can communicate back to the host from which they came. So if you want to build a small server on your host machine which all your applets log into, they can then communicate with each other through the server.

Content Conversion - JDBC and JMS

Can we use File Content Conversion with JDBC and JMS ?

Hi,
How To Use the Content Conversion Module in JMS Adapter - https://websmp106.sap-ag.de/~form/sapnet?_SHORTKEY=01100035870000582377&
check this for JMS content conversion:
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/f02d12a7-0201-0010-5780-8bfc7d12f891
Check the how to guide provided by prabhu and also this link on the XMl To TeXtCoversion Module,
http://help.sap.com/saphelp_nw04/helpdata/en/44/748d595dab6fb5e10000000a155369/content.htm
Ref How To Use the Content Conversion Module in JMS Adapter -
https://websmp106.sap-ag.de/~form/sapnet?_SHORTKEY=01100035870000582377&
See this weblogs which was shown with examples:
How to use SAP's WebAS J2EE's JMS Queue in Exchange Infrastructure
Sync/Async communication in JMS adapter without BPM (SP19)
Async/Sync Communication using JMS adapter without BPM (SP 19)
Exploring JMS and SAP-XI JMS Adaper
Configuring the sender JMS adapter
http://help.sap.com/saphelp_nw2004s/helpdata/en/f4/2d6189f0e27a4894ad517961762db7/content.htm
Configuring the receiver JMS adapter
http://help.sap.com/saphelp_nw2004s/helpdata/en/10/b1b4c8575a6e47954ad63438d303e4/content.htm
Check JMS Adapter section of this blog by Sravya:
Aspirant to learn SAP XI...You won the Jackpot if you read this!-Part III
Also information related to Provider-specific settings are available
http://help.sap.com/saphelp_nw2004s/helpdata/en/cd/d85a9d6fab7d4dbb7ae421f710626c/frameset.htm
Plz do refer the following threads:
JMS Content Conversion - no CR/LF
Message (Data) getting lost after JMS Content Conversion(Sender)
Message (Data) getting lost after JMS Content Conversion(Sender)
Message (Data) getting lost after JMS Content Conversion(Sender)
Regards,
Vinod.

Problem with Using JDBC in Applet

Hi,
i have written an applet to log in (it checks the database, if the username and pasword exists it shows corresponding message). i use access or sql server and applet is started but no message is shown(i think it does not connect to database). here is my code:
import javax.swing.*;
import java.sql.*;
import java.awt.event.*;
import java.awt.*;
public class appletDatabase extends JApplet implements ActionListener {
JLabel l1;
JLabel l2;
JLabel l3;
JTextField tf1;
JPasswordField tf2;
JButton btn;
Connection cn;
Statement st;
String hostname;
public void init() {
hostname = "localhost";
l1 = new JLabel("User Name: ");
l2 = new JLabel(" Password: ");
l3 = new JLabel(" ");
tf1 = new JTextField(20);
tf2 = new JPasswordField(20);
btn = new JButton("Sign in");
Container c = getContentPane();
c.setLayout(new FlowLayout(FlowLayout.LEFT));
c.add(l1);
c.add(tf1);
c.add(l2);
c.add(tf2);
c.add(btn);
c.add(l3);
btn.addActionListener(this);
setSize(300,300);
setVisible(true);
public void actionPerformed(ActionEvent e) {
if (e.getSource()==btn) {
boolean b = check(tf1.getText(),new String(tf2.getPassword()));
if (b) {
l3.setForeground(Color.green);
l3.setText("Username and password exists. ");
else {
l3.setForeground(Color.red);
l3.setText("Username and/or password does not exist.");
public boolean check(String un, String pass) {
String query="SELECT * FROM Table1 WHERE username LIKE'"+un+"'" +
" AND password LIKE'"+pass+"'";
boolean b = false;
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
cn = DriverManager.getConnection("jdbc:odbc:login");
st = cn.createStatement();
ResultSet rs = st.executeQuery(query);
if (!(rs==null))
if (rs.next())
b = true;
rs.close();
st.close();
cn.close();
} catch (SQLException e1) {
e1.printStackTrace();
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
return b;
}

The first thing i notice is that there's a problem with your SQL statement.
To start with you should probably be using PreparedStatements cause it deals with the passing of variables very well and cleanly.
But if you must use a straight statement then it should be like this:
String query = "SELECT * FROM Table1 WHERE username LIKE '"+un+"'" + " AND password LIKE '"+pass+"'";
The fact that you were mising a few spaces wouldn't have helped. Although if you were to use a prepared statement, it would be a lot easier to understand where things were being passed and you don't need to worry about those single quotes for certain values.
Wes

Use of jdbc in applets

hi ,
i am priya i am a learner of java and i am facing some of the problems in using jdbc with applets
i am using ms-access as database and it shows some error messages when i compile the code such as
access denied due to applet security etc
So, please help me in this way so that i can use applets with jdbc
thanx,

I second that. Using JFrame instead of JApplet is easy once you've seen an example:
http://java.sun.com/docs/books/tutorial/uiswing/learn/example1.html
When learning Swing, I can think of only disadvantages to using JApplet over
JFrame. Why do textbooks use applets? Old habits die hard and they
are out-of-date in their view of Java.
Side comment: when learning a new topic, like JDBC, I would
strongly advice you to write the simplest possible code at first.
In other words, skip the Swing and write simple console apps:
1. select and dump the contents of a table.
2. gradually do more sophisticated selects...
3. insert a record into a table using some fixed values.
3. delete records from a table.
4. update records using some fixed values.
Once you are comfortable doing CRUD, and used PreparedStatement!,
then add a GUI. And if your code is well-written, the GUI and the back-end
are separate enough anyway, that you can write and test them apart.

Jdbc in applets

I get the applet panel displayed in a web page. however when the user clicks on the button contained within the panel, nothing happens. In the appletviewer clicking on the button leads to a applet window containing data retrieved from the database (which is required)???

there is lots of stuff on this site about applet signing. It seems complicated at first but its not that bad. In fact, if you had looked first, you would see there is a signed applet forum (!)
anyway, signing the applet is all very well but the crux of it is that applets connecting straight into databases is not good design. If you are just learning, however, then you might try it out but you probably won't (or at least shouldn't) be asked to do it on a job.
maybe if u used a servlet for JDBC, and the applet could connect to that?

___Secure JDBC and Servlets___

Hey all! I have an applet that uses jdbc calls to an oracle database, and servlets calls to oracle's jserv servlet container. It has been requested to make these connections secure.
Can someone please point me into the right direction on information/documentation on performing secure jdbc and servlet calls.
Thanks!

Signed applet communication on Mac

In Denmark homebanking is goin on the net with NetBank. My bank postulates that Mac users cannot participate, as signed applet communication is not supported on Macs.
I find it hard to believe an suspect that ActiveX components are the crook here.
Can anybody confirm my suspicion. Or clear my Bank :-)
I am Macin' 9.0.4ie - MRJ 2.2.5 . Explorer 5.0 or Netscape 6.0

The bank probably says that because it doesn't have any Macs to test it on. Signed applets do work on Macs. However, not all of JRE 1.1 may be implemented in NS 4 or IE 5.0.
I think providing applet only access to Netbanking is a really dumb idea. Fortunately, my bank has not gone the applet route and I can use netbanking services just fine on my Mac with 128 bit encryption.
If I were you, I would just switch to a bank that is more Mac friendly...

Inter Applet Communication across frames - Help Needed

I am trying inter applet communication across frames. For this to happen I am using an intermidiate
class which registers two applets and whenever any applet needs reference of other applet it gets it
through this class.
The page is an important part of a navigation link. So it is loaded many times while traversing through
the site.
Every time I load this page the applet does not paint itself (shows grey or background) and the browser
stops responding. The machine needs to be restarted. This also happens when we keep that page idle for
a long time (say 2 hours - session does not time out but applet hangs). I have used another thread object
which is for utility and accesses the applet in the other frame every 10 seconds or so.
When the applet hangs it does ot throw any exception or JVM error. This happens on certain machines
evrytime and never on some machines. The applet hangs only in Microsoft IE 5 & 5.5 and never in Netscape
4.x.
What could be the problem?
Can anyone help me with this problem? Its a deadline project and I can't get through.
Thanks & Regards,
Rahul

Try making the register and getter methods of the intermediate class static synchronized. Then register the applets in their start() methods and unregister them in their stop() methods. Call the getter method of the intermediate class wherever you need access to another applet and never cache the instance you get. You may have to also synchronize all your start() and stop() methods to the intermediate class, as well as all methods that perform interapplet communication.
Tell me what happenned ...

JDBC and Applet communication

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