FAQ

FAQ Index

1. What is collaborative computing?
2. What is the Java Shared Data Toolkit?
3. Who is the Java Shared Data Toolkit intended for?
4. Why is the version number for the Java Shared Data Toolkit 2.0?
5. Is the Java Shared Data Toolkit a 100% Pure Java technology?
6. What platforms does the Java Shared Data Toolkit support?
7. Where can I download the Java Shared Data Toolkit?
8. How do I provide feedback and bug reports on the Java Shared Data Toolkit?
9. Why can't I get the Java Shared Data Toolkit examples working with LRMP?
10. Are there any debugging facilities in the Java Shared Data Toolkit?
11. How can I sign my JSDT applet?

Collaborative computing means different things to different people. These definitions include:

• Concurrent application usage
• Multi-user application development toolkits
• Interactive desktop conferencing
• Distributed presentations over a network
• Interacting in "virtual" environments
• Workflow; i.e., coordination, transfer and development of information

The Java Shared Data Toolkit (JSDT) implements a multipoint data delivery service for use in support of highly interactive, collaborative, multimedia applications.

It provides the basic abstraction of a session (i.e., a group of objects associated with some common communications pattern), and supports full-duplex multipoint communication among an arbitrary number of connected application entities -- all over a variety of different types of networks.

In addition, this toolkit provides efficient support of multicast message communications. This is accomplished by way of a single send method, and allows the user to define whether or not uniformly sequenced reception of data at all receiving locations is required.

The ability to create shared byte arrays and get and set their values is also provided to session members.

A token-based distributed synchronization mechanism is provided, which can be used to ensure mutually exclusive access to a resource, to perform distributed, multi-application, atomic signalling, etc.

The Java Shared Data Toolkit can be used to help develop any collaborative application that needs to share data amongst one or more users. Some such examples are:

• Shared applications (file editors, whiteboards, VLSI editors)
• Remote teaching and slide presentations
• Distribution of data (news, software distribution, stock updates)
• Chat forums
• Shared simulations and experiments
• Group workflow
• Interaction in virtual worlds
• Network gaming
• Telecommuting

The Java Shared Data Toolkit was originally made available as a technology release (JSDT 1.0) through the early access pages of Sun's Java Developer Connection. There were three updates (JSDT 1.1 through to JSDT 1.3). These releases helped us determine the direction future development on the toolkit should take.

Java Shared Data Toolkit 1.4 was the first commercially available version of this technology.

We then made the Java Shared Data Toolkit freely available with the 1.5 release.

We then continued to make the Java Shared Data Toolkit freely available with the 2.0 release.

This new release is 2.0 (rather than 1.5.1 or 1.6), because some method signature changes were required that broke backward compatibility with JSDT 1.5.

Yes. It it has been certified by KeyLabs as a 100% Pure Java implementation.

Because it's 100% Pure Java, JSDT should work in any environment that has been certified as Java Compatible.

The Java Shared Data Toolkit is available for download via its official home page at

Please follow the links provided on that page.

E-mail the information to jsdt-comments@sun.com.

Before you send us a bug report or feature request, please check the JSDT known bugs/issues to see if this bug/issue is already known.

If you think you have something new, please e-mail us with the following information:

• Short description of the problem.
• Configuration information.
  Please include the hardware platform, Operating System and version (e.g. Intel P160MMX, 32 MB RAM, MS-Windows NT 3.51).
• Steps to reproduce the problem.
• Text of any error message(s) that appeared.
• Simple test program[s] that reproduce the problem.

If we need any additional information we will contact you.

The LRMP version of the Java Shared Data Toolkit requires you to have downloaded LRMP from: http://webcanal.inria.fr/lrmp/index.html and to have added the LRMP jar file to your CLASSPATH.

Make sure that you are starting the LRMP version of the JSDT Registry. This is started with:

You also need to make sure you are using multicast addresses with the -server command line option when starting the examples. For example, the whiteboard server application should be started with something like:

and the whiteboard user application should be started with:

The JSDT package and each of the implementations have been adjusted to use two static boolean variables: "showMessage" and "showStack". If an exception occurs, and "showMessage" is set to true, then an exception message will be printed to stdout. If "showStack" is set to true, then a stack trace will be printed to stderr.

By default, both of these booleans will be set to false. To set them to true, add the following lines at the beginning of your JSDT app:

There was a good article written for the February 1999 edition of the Dr. Dobbs Journal that covers this for the two major Internet browsers. This can be accessed online.