FTP Applet

Could someone kindly tell me if this is possible, and what permissions that applet would need.
I basically want to have an applet FTP files to the server its being hosted on. The applet will need to FTP files to various directories on the server thats hosting the applets.
Thanks in advance....
Kirk

I've seen something like this in the GNU web site (www.gnu.org)...
But....read the caveat that comes with the Java program
V.V.

Similar Messages

Allowing file read on user PC to FTP Applets?

Hi! I searched around the forum and found a few posts on something close to what I am looking for.
This is my dilema. I created an applet that will accept parameters from the html file that loads it. The parameters include "user", and "password" required to log into the FTP site and the file paths of the files that the user wants to upload to the site. Well the applet starts and loads some of the awt components and then just stops. No activity. It runs fine in JBuilder 8 (the files are uploaded to the ftp site) but nothing happens if the applet is run in the browser.
I looked around the forum and saw that I need to sign the applet so that it will be allowed to read files on the user PC. Well how exactly do I do this and what do I need to do it?
I would appreciate any help!!!
Thank you in advance!
Leo.

All is well! I just had to sign the applet and it works like a charm!
Now I have a different issue though! I tried running the applet on Mac OS 9 and it gives me an error stating that a class has not been difined?
If anyone has any info or suggestions here I would really appreciate the input!
Thanks!

Signed applet : problem signing jar files that are in build path

Hello,
I have a problem while trying to create an ftp applet.
I use org.apache.commons.net.ftp and i build path for commons-net-1.1.4.jar and then i build my classes.
When i create a jar file with my classes and after signing it, it works under eclipse but not on a web page.
I had signed commons-net-1.1.4.jar before to build the path in eclipse but commons-net-1.1.4.jar is not in my jar file.
What is the way to sign applet correctly even if some jar ressources are in eclipse build path.
Thank you

You were right!!!
I'm not sure what to write down in the formsweb.cfg (configuration file) , following the instructions on the on-line help of Developer Forms 10g , in step 9..
The step 9 says...
Because in this release the JACOB code is in an external Jar file and not incorporated into frmwebutil.jar, it needs to be downloaded. To do this, change the WebUtilArchive setting to read: webUtilArchive=/forms/webutil/frmwebutil.jar,/forms/webutil/jacob.jar
The doudt is pointed to the fact that the frmwebutil.jar isn't in the ORACLE_HOME\forms\webutil path but it is ORACLE_HOME\forms\java path.
Also , these paths referenced in webUtilArchive are physical paths in a Unix system or they are logical paths in a url?
Simon

Log applets errors

Hi
Is there a way that the errors,who are being thrown at an applet on the internet; being logged at an file on the server
thx at 4 hand
Thomas

And what errors will be logged then? How am I supposed to know?? It's your applet! Read about Log4J a bit: you define what gets logged
I have a
ftp-applet so he should log the connection errors and
so. Is this posible?Absolutely. It won't be automatic, though. You need to write the logging code that does this. It's pretty straightforward, though, and the same code can be used to log to a console, a file, a JMS queue or whichever else you choose. The destination of the logging is configured outside of your code

AccessDeclaredMembers Exception

Hi,
I am developing an FTP Applet using swings. This applet displays the client side as well as the server side directory structure for the user to upload and download files. I am also using a database to control the permissions of the files and folders on the ftp server.
The problem is, my applet works fine on Windows 95, Windows 98, WIndows 2000 Advanced Server and Windows 2000 Professional. But it gives problems with WinNT 4.0 (IE5.5, SP6)
I have no idea of this erratic behavior. The problem is i get a security exception saying
accessDenied: java.lang.RuntimePermission accessDeclaredMembers
Any suggestions?

can i have the source code of your fpt applet? tnx!

Applet with FTP

Hi,
I am writing a java applet for an client. The applet will reside on the server and when a user will execute it, it will list the connected readers from the computer and will read it's smart card's data when he selects a reader from his choice. So far it is done. Now another portion of the work is that this data should be written on the FTP server in the form of a file. Now problem is applets executes on the client side and I have to have provide some mechanism by which i could write files on the FTP server. I am using the following code for this:
URL url = new URL("ftp://xyx.it:[email protected]/httpdocs/abc_direc/test.txt1;type=i");
URLConnection urlconnection = url.openConnection();
OutputStream outputstreamObj = urlconnection.getOutputStream();
String datatoWrite= "Texting strings to write";
outputstreamObj.write(datatoWrite.getBytes());
outputstreamObj.close();
Code the working fine but as you can see i have to provide FTP credentials into the code. Now my client is asking that how I will change it when later if he needed and 2ndly if I will provide a file to put credentials information then he has security concerns that it can be read by someone.
Here I am asking your experts suggestions that how should i do it so that both concerns of my client that is:
1. changing credentials (FTP address,username & password) later on without recompiling the code
2. Security concerns
can be fulfilled.
Many Thanks

Thanks,
But when i sign my archive and jar files,
why i need to implement a SecurityManager or is that a wrong information.
And when i want the applet also used by Netscape Users is it enough to sign the applet or must i implemet the netscape.security.PrivilegeManager ??
I want that when the applet started a window pop up and ask the user if he support the Applet functionality.
So he only said yes and it will run

FTP in Applet

I have downloaded third party FTP package. I am making a ftp connection in applet using this third party
package. When i run my applet using Appletviewer,
i got the following exception:
java.security.AccessControlException: access denied
I created policy file with full permissions and login details and server details are correct.
what is the problem ?
Pls help me !!

Applets run in a sandbox that prevents them from doing many things, such as connecting to a server other than the one they were loaded from.
You can fix this in a couple of ways. The standard way is to sign the applet, so that the user will agree to allow your applet to do that. The other way, which is pointless in most cases, is to create a policy file (as you did) and to install it in the correct location in the user's computer (which you apparently didn't, and is impractical in the real world anyway).

Remote Java applet ftp hangs

Hi,
I have a java applet that ftps files back to a server. It is correctly signed and can access files on the hard drive.
When downloaded and run as a local applet it works fine, however when downloaded as a remote applet it just hangs at the line
FTPClient ftp = new FTPClient();
No error messages, no clue, just gets no further than that.
Apologies if this is a bit vague or missing any vital information, but java isn't really my thing....
Cheers
Ralph

Thanks, I'm running 1.6.0_12.
No, FF has the option but nothing happens when I click on it. I just upgraded today from v3.5.x because under that version the option is there but when clicked on it deactivates the option. I first tried upgrading to the latest console plugin for FF. As soon as I installed it and FF restarted it said that it was desupported and next time it re-started it just does nothing as I said. So I upgraded to v3.6.13 and re-started and same same. It says it's de-supported. I dunno.
Anyway, I went to the System tray Java icon and right-clicked on it and clicked on properties. Under 'Advanced | Java Console' I see I had it as "hide Console". I changed it to "Show Console". When I started an Applet I got the console. I closed it and now I don't get it again. Weird.
I just cancelled the Java icon in the system tray and restarted it. I checked it back to Hide the Java Console and "Apply", then Show it, and "Apply". Then I started an Applet. No dice. I started it again and Got the Console. But is seems if I close it I can't get it back without all this riggamorole.

Finding other files in same ftp to use in applet

I have created a signed applet that can access, write, and delete files within the same folder as the jar file containing the class (signed applets require jar files to hold the class). On my computer I use
String dir = getCodeBase().getPath(); to locate whatever directory the jar file may be in, which works. However, when I put everything (jar, files, signed html applet, etc) on my ftp (same setup as on my computer) and try to run the applet online, it cannot find the files. How do I solve this?

I see... I am not very familiar with client/server interactions. I have made a very simple text messaging before. However, it only allowed one connection a time. Is it possible to create a server that can receive any number of connections to send data needed for the client's applet and receive specific commands to modify certain data on the server side?
In a very basic example:
A server keeps a Serializable file containing a list of names. Any number of client can visit the applet's web page, which automatically makes the connection to the server. The client is then provided with the list of names and the options (JButtons with JTextFields) to add a name, modify a name, or delete a name which changes the file's information.
If such is possible, could you point me to a tutorial that mainly deals about creating this type of server.

How do I use applet.onScriptStatus?

When we are launching the JVue applet quickly, multiple times in a row, we sometimes get into trouble and the feeling we get is that Java, or something else, at the client side, is pushed too hard. So, we have tried various ways to ask the currently executing viewer instance if it is "ready", or at least "half ready" before launching the next instance. We have had different success with different approaches, all the way from just waiting for X seconds before we launch the next viewer instance, to use methods like applet.waitForLastMethod. We always send in a JavaScript method to the ONINIT parameter of the applet, so that at least we are not trying to load a new instance before the applet is loaded. We have also tried the approach of calling getFileName, and when it returns non-null we at least know the document is loading and we can launch another viewer. The best thing would of course be if we could know then the loading/rendering is 100% complete.
The other day I found this method in the documentation:
ftp://active-project.com/jVue/docs/JavaDocs/VueBean/com/cimmetry/jvue/JVue.html#onScriptStatus(int, java.lang.String, java.lang.Object)
It sounds like this method could be used to "wait" until things have settled down before we give green light to process the next document. But it is not self evident how this method can be used. I have searched the web and can not find one single example on how it is used.
Any ideas?
Thanks!
/Mathias

The onScriptStatus is the implementation of the ScriptStatusListener interface and should not be called from outside.
You may use JVue.setStatusListener(String statusListener) : The statusListener is the name of a JavaScript function that will be called (by onScriptStatus) each time a script command gets executed.
The statusListener parameters are similar to the onScriptStatus params.

Problem Launching Java Applet with Plug-in: Version 1.4.2_01

Hello out there:
I recently installed j2re-1.4.2_01 on my home computer but have been unable to access Web sites emmploying JAva applets. The following is an email exchange with Jeff Hall of Lowell Observatory, manager of an educational site hosted by Lowell, trying to resolve my problem. The messages are better understood if read in reverse order.
I'm hoping that someone will recognize the source of my problem and can recommmend a solution. I would appreciate any help offered.
Thanks,
Mike Coucke
Hi Jeff:
Well, I guess the problem lies with me somewhere. Here's my answer/status to your questions/suggestions:
1) I'm using MS Windows Me version 4.90.3000
2) I do have the directory C:\Windows\.jpi_cache\jar\, but the only thing in it is an empty folder labeled "1.0". The file LP.jar does not exist anywhere on my hard drive.
3) I tried several game sites that utilized Java applets and got the same results: the Java cup in the upper left corner followed a few seconds later by the red "X". So, evidently the problem is somewhere on my end.
I'm going to post our email exchanges in a Java Users Forum managed by Sun to see if anyone out there can solve my problem. However, if you have any more suggestions, I'll be glad to try them.
Thanks for the help.
Mike Coucke
[email protected]
----- Original Message -----
From: "Jeffrey Hall" <[email protected]>
To: "'Mike Coucke'" <[email protected]>
Sent: Friday, September 05, 2003 1:02 PM
Subject: RE: Registration with Lowell Education Online
Mike,
Rats! What version of Windows are you using? It's a little strange to
see the user directory set to C:\Windows; if you're using XP, I'd expect
it to be something like C:\Documents and Settings\Mike Coucke. In any
event, the output that is of concern is these two lines:
java.lang.ClassNotFoundException: LPRemote.class
Caused by: java.net.UnknownHostException: proxy
It looks like your browser is not finding our server's IP when it comes
time to download the necessary Java code.
LPRemote.class is the fundamental code that runs LOPARC, and your
browser should be downloading it automatically when you click connect.
LPRemote.class is stored along with a bunch of other classes in a file
called "LP.jar" that you download from our server. So, if you go to C:
in Windows Explorer and do a file search for LP.jar, you should find it.
On my machine, it's stored in a directory called ".jpi_cache\jar\" in my
user home directory. Let me know if you have this file, or the
jpi-cache directory.
One other thing you might try is going to a different site that you know
uses Java applets -- I think some of the online game rooms at Yahoo use
Java. See if other sites that use Java load correctly. Then we'll know
if it's our server specifically, or a more general problem on your end.
Jeff Hall
Lowell Observatory
Hello Jeff:
I still have the Java "blues". I followed your instructions, but am still unable to launch a LOPARC session. After an initial failure, I uninstalled all three Java versions I had (1.4.0, 1.4.1, 1.4.2), then reinstalled 1.4.2_01 from the Sun website.
Now, when I try to launch LOPARC, I initially get a blank window with the Java cup in the upper left corner. After about 20 seconds, the cup changes to a red "X". During those 20 seconds, the following appear in the IE message bar at the bottom of the window: "Applet LPRemote notinited" (their spelling) which changes to "Loading Java Applet Failed..." when the red "X" appears.
Following is a copy of the log from my Java Console during all of this:
Java(TM) Plug-in: Version 1.4.2_01
Using JRE version 1.4.2_01 Java HotSpot(TM) Client VM
User home directory = C:\WINDOWS
Proxy Configuration: Manual Configuration
Proxy: http=proxy,https=proxy,ftp=proxy,gopher=proxy
Proxy Overrides:
c: clear console window
f: finalize objects on finalization queue
g: garbage collect
h: display this help message
l: dump classloader list
m: print memory usage
o: trigger logging
p: reload proxy configuration
q: hide console
r: reload policy configuration
s: dump system properties
t: dump thread list
v: dump thread stack
x: clear classloader cache
0-5: set trace level to <n>
load: class LPRemote.class not found.
java.lang.ClassNotFoundException: LPRemote.class
at sun.applet.AppletClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.applet.AppletClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.applet.AppletClassLoader.loadCode(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.plugin.AppletViewer.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: proxy
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.plugin.net.protocol.http.HttpClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.net.www.http.HttpClient.privilegedOpenServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.plugin.net.protocol.http.HttpClient.<init>(Unknown Source)
at sun.plugin.net.protocol.http.HttpClient.New(Unknown Source)
at sun.plugin.net.protocol.http.HttpURLConnection.createConnection(Unknown Source)
at sun.plugin.net.protocol.http.HttpURLConnection.connect(Unknown Source)
at sun.plugin.net.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.HttpURLConnection.getResponseCode(Unknown Source)
at sun.applet.AppletClassLoader.getBytes(Unknown Source)
at sun.applet.AppletClassLoader.access$100(Unknown Source)
at sun.applet.AppletClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
... 10 more
I followed this up by executing the following three console commands:
"dump system properties"
"dump classholder list"
"dump thread list"
and obtained the following listings:
Dump system properties ...
acl.read = +
acl.read.default =
acl.write = +
acl.write.default =
application.home = C:\PROGRA~1\JAVA\J2RE14~1.2_0
awt.toolkit = sun.awt.windows.WToolkit
browser = sun.plugin
browser.vendor = Sun Microsystems, Inc.
browser.version = 1.1
deployment.javaws.cache.dir = C:\WINDOWS\.javaws\cache
deployment.javaws.jre.0.enabled = true
deployment.javaws.jre.0.location = http://java.sun.com/products/autodl/j2se
deployment.javaws.jre.0.osarch = x86
deployment.javaws.jre.0.osname = Windows
deployment.javaws.jre.0.path = C:\Program Files\Java\j2re1.4.2_01\bin\javaw.exe
deployment.javaws.jre.0.platform = 1.4
deployment.javaws.jre.0.product = 1.4.2_01
deployment.javaws.jre.0.registered = true
deployment.javaws.version = javaws-1.4.2_01
deployment.system.cacerts = C:\PROGRA~1\JAVA\J2RE14~1.2_0\lib\security\cacerts
deployment.system.home = C:\WINDOWS\Sun\Java\Deployment
deployment.system.jssecacerts = C:\PROGRA~1\JAVA\J2RE14~1.2_0\lib\security\cacerts
deployment.system.profile = C:\WINDOWS
deployment.system.security.policy = file:/C:/WINDOWS/Sun/Java/Deployment/security/java.policy
deployment.user.cachedir = C:\WINDOWS\Application Data\Sun\Java\Deployment\cache
deployment.user.certs = C:\WINDOWS\Application Data\Sun\Java\Deployment\security\deployment.certs
deployment.user.extdir = C:\WINDOWS\Application Data\Sun\Java\Deployment\ext
deployment.user.home = C:\WINDOWS\Application Data\Sun\Java\Deployment
deployment.user.jssecerts = C:\WINDOWS\Application Data\Sun\Java\Deployment\security\deployment.jssecerts
deployment.user.logdir = C:\WINDOWS\Application Data\Sun\Java\Deployment\log
deployment.user.profile = C:\WINDOWS\Application Data
deployment.user.security.policy = file:/C:/WINDOWS/Application%20Data/Sun/Java/Deployment/security/java.policy
deployment.user.tmpdir = C:\WINDOWS\Application Data\Sun\Java\Deployment\cache\tmp
file.encoding = Cp1252
file.encoding.pkg = sun.io
file.separator = \
file.separator.applet = true
http.agent = Mozilla/4.0 (Windows Me 4.90)
http.auth.serializeRequests = true
https.protocols = SSLv3,SSLv2Hello
java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment
java.awt.printerjob = sun.awt.windows.WPrinterJob
java.class.path = C:\PROGRA~1\JAVA\J2RE14~1.2_0\classes
java.class.version = 48.0
java.class.version.applet = true
java.endorsed.dirs = C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\endorsed
java.ext.dirs = C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\ext
java.home = C:\PROGRA~1\JAVA\J2RE14~1.2_0
java.io.tmpdir = C:\WINDOWS\TEMP\
java.library.path = D:\PROGRAM FILES\INTERNET EXPLORER 6;.;C:\WINDOWS\SYSTEM;C:\WINDOWS;D:\PROGRA~1\INTERN~1;;C:\WINDOWS;C:\WINDOWS\COMMAND
java.protocol.handler.pkgs = sun.plugin.net.protocol|sun.plugin.net.protocol
java.runtime.name = Java(TM) 2 Runtime Environment, Standard Edition
java.runtime.version = 1.4.2_01-b06
java.specification.name = Java Platform API Specification
java.specification.vendor = Sun Microsystems Inc.
java.specification.version = 1.4
java.util.prefs.PreferencesFactory = java.util.prefs.WindowsPreferencesFactory
java.vendor = Sun Microsystems Inc.
java.vendor.applet = true
java.vendor.url = http://java.sun.com/
java.vendor.url.applet = true
java.vendor.url.bug = http://java.sun.com/cgi-bin/bugreport.cgi
java.version = 1.4.2_01
java.version.applet = true
java.vm.info = mixed mode
java.vm.name = Java HotSpot(TM) Client VM
java.vm.specification.name = Java Virtual Machine Specification
java.vm.specification.vendor = Sun Microsystems Inc.
java.vm.specification.version = 1.0
java.vm.vendor = Sun Microsystems Inc.
java.vm.version = 1.4.2_01-b06
javaplugin.maxHeapSize = 96m
javaplugin.nodotversion = 142_01
javaplugin.proxy.config.list = http=proxy,https=proxy,ftp=proxy,gopher=proxy
javaplugin.proxy.config.type = manual
javaplugin.version = 1.4.2_01
javaplugin.vm.options = -Djava.class.path=C:\PROGRA~1\JAVA\J2RE14~1.2_0\classes -Xbootclasspath/a:C:\PROGRA~1\JAVA\J2RE14~1.2_0\lib\plugin.jar -Xmx96m -Djavaplugin.maxHeapSize=96m -Xverify:remote -Djavaplugin.version=1.4.2_01 -Djavaplugin.nodotversion=142_01 -Dbrowser=sun.plugin -DtrustProxy=true -Dapplication.home=C:\PROGRA~1\JAVA\J2RE14~1.2_0 -Djava.protocol.handler.pkgs=sun.plugin.net.protocol
line.separator = \r\n
line.separator.applet = true
os.arch = x86
os.arch.applet = true
os.name = Windows Me
os.name.applet = true
os.version = 4.90
os.version.applet = true
package.restrict.access.netscape = false
package.restrict.access.sun = true
package.restrict.definition.java = true
package.restrict.definition.netscape = true
package.restrict.definition.sun = true
path.separator = ;
path.separator.applet = true
sun.arch.data.model = 32
sun.boot.class.path = C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\rt.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\i18n.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\sunrsasign.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\jsse.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\jce.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\lib\charsets.jar;C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\classes;C:\PROGRA~1\JAVA\J2RE14~1.2_0\lib\plugin.jar
sun.boot.library.path = C:\PROGRAM FILES\JAVA\J2RE1.4.2_01\bin
sun.cpu.endian = little
sun.cpu.isalist = pentium i486 i386
sun.io.unicode.encoding = UnicodeLittle
sun.java2d.fontpath =
sun.net.client.defaultConnectTimeout = 120000
sun.os.patch.level =
trustProxy = true
user.country = US
user.dir = C:\WINDOWS\Desktop
user.home = C:\WINDOWS
user.language = en
user.name = Michael G. Coucke
user.timezone =
user.variant =
Done.
Dump classloader list ...
codebase=http://kraken.lowell.edu/, key=http://kraken.lowell.edu/,IONJava/classes/ion_16.jar,IONJava/classes/LP.jar, zombie=false, cache=true, refcount=1, info=sun.plugin.ClassLoaderInfo@109de5b
Done.
Dump thread list ...
Group main,ac=11,agc=2,pri=10
main,5,alive
AWT-Windows,6,alive,dameon
AWT-Shutdown,5,alive
Java2D Disposer,10,alive,dameon
AWT-EventQueue-0,6,alive
Group Plugin Thread Group,ac=3,agc=0,pri=10
Main Console Writer,6,alive
AWT-EventQueue-1,6,alive
TimerQueue,5,alive,dameon
Group http://kraken.lowell.edu/-threadGroup,ac=2,agc=0,pri=4
thread applet-LPRemote.class,4,alive
AWT-EventQueue-2,4,alive
Done.
I'm not a Java expert, so this may be more information than you ever wanted to see.
Once again, I hope that you can help. My experience has been that I usually have some obscure option set incorrectly and that causes me great grief.
Thanks fo your help,
Mike Coucke
[email protected]
----- Original Message -----
From: "Jeffrey Hall" <[email protected]>
To: "'Mike Coucke'" <[email protected]>
Sent: Thursday, September 04, 2003 11:48 AM
Subject: RE: Registration with Lowell Education Online
Hi Mike,
Try it now. I think this problem has arisen because Sun just
released a new version of the Plug-in (1.4.2), and when we released the
public beta of LOPARC, only one relevant version (1.4.0) was available
and the LOPARC code was written to look for that by default. I have
just recoded the relevant routines so they should now cause your browser
to simply pick up the latest 1.4 version of the Plug-in you have
installed, whatever it is. I "broke" Java on my machine to replicate
your problem, and the code I inserted today did fix it. Hopefully it
will have the same effect for you. I am running IE 6 and plugin
1.4.2_01 (as accessed via Tools->Sun Java Console).
One broader problem: some (non-LOPARC-specific) users on the Sun
forums have reported the "JRE collision" you are seeing when multiple
versions of the Plug-in are installed on the same machine. So if the
fix I made to our code doesn't work, one option would be to uninstall
all Java components from your computer and do a fresh install of the
latest runtime environment.
Let me know how/if this works. Thanks for the feedback and for your
patience.
Best regards,
Jeff Hall
Lowell Observatory
-----Original Message-----
From: Mike Coucke [mailto:[email protected]]
Sent: Wednesday, September 03, 2003 6:30 PM
To: [email protected]
Subject: Re: Registration with Lowell Education Online
Hello Jeff:
So far, I have been unable to launch a LOPARC session. I repeatedly
get the following error message:
"Exception: java.lang.ClassNotFoundException: LPRemote.class"
My browser is MS Internet Explorer version 6.0.2800.1106 Initially I was
using Java Plug-In version 1.4.1 and received the error message. I went
to the Sun website and downloaded/installed Java Plug-In version 1.4.2
and still get the message.
Before I try to launch LOPARC, I can select Tools->Sun Java Console from
IE's pull down menu to check my Java Plug-In version. When I try to
launch LOPARC, I get the following message:
"Applet(s) in this HTML page requires a version of Java different from
the one the browser is currently using. In order to run the applet(s)
in this HTML page, a new browser session is required, press 'Yes' to
start a new browser session." If I select 'No', I get the following
message: "Java Plug-in detected JRE collission"
If I select 'Yes', a new browser window opens and then I get the first
message above.
Can you help?
Mike Coucke
[email protected]
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Monday, September 01, 2003 5:30 PM
Subject: Registration with Lowell Education Online
September 1, 2003
Dear Michael Coucke:
Thank you for registering with Lowell Observatory's online education
site. We hope you enjoy using it and visit regularly as we continue to
expand its features and capabilities. This is a one-time welcoming
email.
For your records, your user ID is xxxxx, and your password is #########.
You'll need to supply these each time you log in.
This site gives you access to research-grade equipment including a 16"
telescope, CCD detector, and image processing software. Our online
archive of data is now available 24/7. The telescope will be opening to
our onsite users in May, and on select nights to the Internet at large
in June.
We have designed this site so you don't need a huge monitor or a
supercomputer to use it. All pages are viewable on screens running at
800x600 resolution or higher. To use LOPARC, you'll need a Java-enabled
browser with the Java 1.4 plug-in installed. If you don't have the
plug-in, you'll be prompted to download it the first time you attempt to
connect. This is an admittedly large (9 MB) but one-time-only download.
This site works correctly under Internet Explorer version 5 or higher.
If you use Netscape, you must be running version 6 or higher, and
display or applet behavior anomalies may occur.
If at any time you can't connect to our server, simply try again later.
We do experience several power outages each year, particularly during
Flagstaff's summer thunderstorm season. Our server is fully protected
and backed up, and can be quickly brought back on line, but any active
user sessions will be lost. Thanks for your patience during these
inevitable downtimes.
Your questions, comments, suggestions, and bug reports about this site
are always welcome. On behalf of the LOPARC development team, thanks
for signing up!
Jeffrey Hall
Assistant Research Scientist
Associate Director, Education and Special Programs
Lowell Observatory
Flagstaff, Arizona

Hi Mike,
I see this in your logs:
Java(TM) Plug-in: Version 1.4.2_01
Using JRE version 1.4.2_01 Java HotSpot(TM) Client VM
User home directory = C:\WINDOWS
Proxy Configuration: Manual Configuration
Proxy: http=proxy,https=proxy,ftp=proxy,gopher=proxy
Proxy Overrides:
I just helped my Dad set up his computer with a new
cable modem, and had the situation where we couldn't
access any secure Web sites. The cable folks had us
disable the proxy. It looks like the error message is
saying it can't find your proxy server, and the logs
you posted say that you've decided to configure your
proxy manually, rather than using the settings from
IE (which is how mine is set up in the plugin
control panel.)
Could that be the problem?
--Steve

Transferring files from users mashines on the server. Uploading with applet

I'm trying to create applet that would do uploading of user file on the server.
I'm woundering, Is there any ways to use java applet to open a file on user mashine into a stream and transfer it thought socket into
server? Is there any good solution that do uploading with java applet? (I can't use CGI or PHP)
I just noticed that applets don't support FileInputStream. How could I in general get information from user file?
Ok. Thanks for ideas that you gave me. But there are useless. All that I can use is only HTTP. Unfortunately no FTP, no Web Start application.
looking for help

well, i don't work a lot with applets because of their inherent limitations. but my guess would be that you have to somehow use a signed applet. of course that doesn't help with the FileInputStream problem you are talking about.
if i were going to do it and i couldn't use FTP, i'd write a WebStart app that calls servlets (sending it byte arrays) and the servlets will construct the files on the server...
i have no clue how you are going to do what you want...

Read file from URL and save to FTP

Hi,
I have worked in java few years back, now I am out of touch. My friend asked me to create an applet program for him which he can use to download a file from remote location to his ftp server.
For e.g.
File
http://www.demo.com/filename.avi
Saved to
ftp://username:password@ftpsite_address/foldername
I was searching for the classes which I can use to achieve this functionality.
To save to FTP
URL url = new URL("ftp://username:[email protected]/folder/filename");
URLConnection urlconnection = url.openConnection();
long l = urlconnection.getContentLength();
OutputStream outputstream = null;
outputstream = urlconnection.getOutputStream();Using the above code I can get the outputstream to which I can write.
I am now stuck here, have some doubts.
What all classes should I use to read a file like
http://www.demo.com/filename.avi
I know I can use URL to open connection to URLS and then streams to read the url.
I am interested in knowing the class which I should use to read any type of file. File can be zip/avi/rar or anything else.
What all method of the class should I use to read the file which will support all type of files.
Which classes should I use to write the files. The files are going to be huge in terms of size.
I have searched everywhere but every place different classes are used.
Any help is appreciated.

Ok now I have started coding but facing a problem.
[PHP]try {
     URL url = new URL("http://url_to_file/test.txt");
     URLConnection urlconnection = url.openConnection();
     long l = urlconnection.getContentLength();
     fTextArea.append("Content Length = " + l);
     BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
     String line;
     while ((line = in.readLine()) != null)
          fTextArea.append("\n"+line);
     in.close();
} catch (Exception e) {
fTextArea.append(e);
return;
[PHP]
When I run this code locally it works fine but when run in browser it shows security exception
java.security.AccessControlException: access denied (java.net.SocketPermission site:80 connect,resolve)
What should I do to resolve this error. Sorry for being such a noob but do not have much info about this.

Applet Download Incomplete

I'm having a problem with the download of a large applet (approx. 1MB) getting cut short.
Everything appears normal. The Java Extension Installation progress window comes up. But when it tries to run the applet it gets "load: class <className> not found" where <className> is the name of the class in my CODE parameter. It appears that on occasion the download of the jar gets cut off. When I search the browser's cache, I find a jar file that has fewer bytes than it should. In order to initiate a retry, you have to delete the jar file from your browser's cache, close all your browser windows so that the Plug-in with its truncated jar file stops running, and load the HTML page again. It appears that it checks the timestamp of the jar file in your cache and the one on the server and decides that it doesn't need to download it again. But if you delete it from your cache, it forces a retry.
I never have this problem when I open from my hard drive. I've never had the problem with a cable modem connection. I've had it once from a corporate LAN hitting an internet server (i.e., outside corporate WAN). I've had people report the problem with dial-up connections. My theory is that whatever the Plug-in is using to download the applet is more sensitive than either HTTP download or FTP.
I realize that if I used the cache options, once a user has successfully downloaded the applet, there's no more problem. But it makes for a crummy initial user experience if they're unfortunate enough to have their download truncated. Also, given the fact that it doesn't report the download problem and instead says it can't find a class, it makes it look like I'm delivering an untested applet. Not good.
Has anybody else experienced this problem? Is there anything you can do about it? I couldn't find a bug report on it. Is there one?

I get a similar problem which we have diagnosed to be either a network problem (i.e congestion) or a problem with the firewall and bypass proxy settings. The firewall itself slows downloads because the firewall is funnelling connections through it causing a congested network. Our solution (intranet) is to include the correct bypass proxy settings in the browser, though this might not be a very good answer for an internet.
I have one other thing you can make sure you are doing if you are developing your applet locally then moving it to another platform. If you ftp files (like your applet) between machines, especially across different platforms like nt and unix/linex, you might want to verify that you are using binary (and not ascii) transfer to make sure you get all your bytecode. I think if you use another method like remote copy, this is not a problem. I hope this helps.
Rodger

How can I make an applet look to the current directory to read a txt file in?

I am using a File class passing only the file name as the contructor but forte still looks in "C:\forte_jdk\forte4j\bin\Events.txt" which is not my current directory for the project.
If leave it and ftp this applet to my web site I get an IOException.

I always find visual aids helpful. See below for screenshots & discriptions.
01. The Basics
When you create a new site & go into design view (in the example below it's the Home page), you'll see the following.
The white box is your page.
The grey box outside of that is your browser area.
The black & white checkered area is the Adobe Muse CC application chrome.
02. Add Box
Draw / Add your rectangle or text frame (text tool). I drew a rectangle, gave it a fill color of blue & turned the stroke from 1 to 0.
03. Extend & Snap to Browser Edge (Left)
Click, hold and drag your mouse on the center adorner (adorner is the little squares that you can grab to resize your rectangle) until you resize your rectangle to the browser edge (the dark grey area) until you see a red line. This means you've 'snapped' one of the rectangle's edge to the browser edge.
04. Extend & Snap to Browser Edge (Right)
Repeat the process except do this for the right edge. In truth, it doesn't matter in which order you resize your rectangle to snap to the browser edges. The key thing is to be sure to do this for both sides of the rectangle & snap it to the browser edge (see the red line).
05. You're done! Preview.
06. Bonus!
Once again, you can make rectangles or text frames 100% width, BUT you can't do this with placed images.
However, you can do this with a rectangle or text frame. Then set the Fill of either the rectangle & text frame to be an Image & set the Fitting to 'Scale to Fill.'
(see below for example - I used a rectangle & changed it's Fill property)
Now when I preview, the image is 100% width. In truth, it's a 100% width rectangle with a fill of an image.

FTP Applet

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