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Unable to view Applets due to class not found error.

vijayalayan selvaraj
Greenhorn

Joined: Sep 11, 2007
Posts: 5
We are currently facing issues in our upgrade to Java JRE 1.6 & above from JRE 1.4 on displaying certain information. Our applets are built in a way like at runtime it will access certain jar files ( tibco jar files) and use them to parse the incoming messages. The following will give a summary of the issue.

We were using Jre 1.4 in our systems previously. With JRE 1.4, we have a system where we use java applets to display data over the network in the websites. The java applets will use a jar file (TIBRVJ.jar file available in C:\TIBCO\TIBRV\8.3\LIB\) folder. The way we facilitate this is by including –cp “C:\TIBCO\TIBRV\8.3\LIB\TIBRVJ.JAR in the Java runtime parameter settings. However post upgrade to JRE 1.6, we are getting errors in our systems due to the upgrade as specified below. the only way we are able to avoid this issue is by placing the Jar file in JRE/lib/ext folder. it also requires changes in our Java.policy file to provide access to this.

Error Codes
---------------------------------------------------
‘java.lang.NoClassDefFoundError: com/tibco/tibrv/TibrvMsgCallback”


We would like to know why the tibrv. jar file is not picked from the classpath set on the Java Runtime Parameters, but being picked only after placing it in the ext/bin directory and changing Java policy files in JRE 1.6 and higher versions.
Maneesh Godbole
Saloon Keeper

Joined: Jul 26, 2007
Posts: 10451
    
    8

Welcome to the Ranch.

Looks like you got a web page (with the embedded applet) served by the server, running on the client.
So where are your jars placed? Client or server?


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vijayalayan selvaraj
Greenhorn

Joined: Sep 11, 2007
Posts: 5
Hi maneesh,
Thanks for your response. yes you are right.. The jar files are available in client and the changes needs to be done in Client server lib/ext folder only to enable the embedded applet to work.
Maneesh Godbole
Saloon Keeper

Joined: Jul 26, 2007
Posts: 10451
    
    8

I would not recommend that. Your current problem is exactly one of the reasons why such an approach is not recommended.
You can specify your dependent jars in the ARCHIVE tag after placing all your jars on the server side
When the applet runs on the client side, these jars will be automatically picked up as required.

Recommended reading
http://docs.oracle.com/javase/1.4.2/docs/guide/misc/applet.html
http://docs.oracle.com/javase/tutorial/deployment/applet/html.html
http://docs.oracle.com/javase/tutorial/deployment/deploymentInDepth/runAppletFunction.html
vijayalayan selvaraj
Greenhorn

Joined: Sep 11, 2007
Posts: 5
Hi Maneesh,
many thanks for your response. There is one problem with keeping the files on the server. The jar files are licensed products and cannot be maintained in server. That is the reason why we have to rely on this method. Is there any other alternative for this approach.

Many thanks.
Vijay.
Maneesh Godbole
Saloon Keeper

Joined: Jul 26, 2007
Posts: 10451
    
    8

vijayalayan selvaraj wrote:There is one problem with keeping the files on the server. The jar files are licensed products and cannot be maintained in server.

Care to explain what you mean by "maintained on the server" and how licensing affects it?
vijayalayan selvaraj
Greenhorn

Joined: Sep 11, 2007
Posts: 5
We are having a website which uses third party software (tibco) which is a licensed product used for efficient message broadcasting. the messages that we publish will be read only by these softwares and whoever having this software will be able to pick up the messages. In order to ease this process we developed a website which has applet code and making use of the clients who are having license to hold tibco software. we reuse the jar files in the applet code which wil run on the client machine.

If we maintain the jar file in the server, it will open access to all the people in the network to make use of the software and receive messages.We cannot allow that as the software that we are using is a licensed product and many clients are currently paying the cost associated with it.
vijayalayan selvaraj
Greenhorn

Joined: Sep 11, 2007
Posts: 5
Hi,
Can you please share some views on this issue. We are in a very critical stage of the project and need to find a resolution as early as possible.
 
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