What is DSJ?

The Borland Deployment Server for Java (DSJ) gives your full-fledged Java applications the convenience of applet deployment without applet restrictions. Applications are installed once on a server, then are seamlessly accessed by remote clients on any platform. Updates are centrally administered and immediate. Access may be monitored.

Benefits for the developer include:

• Developed applications are more powerful because they are not subject to the security restrictions of applets.
• Developers are relieved of coordinating deployment issues with other departments.
• Management can track application usage.
• IS department has a dramatically simpler network infrastructure to maintain.
• QA doesnÆt need to test for differences introduced by browser vagaries caused by version or platform.
• Applications can be deployed to platforms without a Java-enabled browser that supports the version of the JDK used in development (either earlier or later).
• May obviate big site licenses for browsers in larger organizations. Not having browsers saves costs for training, maintenance, updates, and loss of productivity.
• Development can target lower-end machines, because target will not require a full-fledged browser.
• Widens the number of potential target platforms.
• Developers donÆt have to code around bugs in particular browsers.
• Maintains security within the firewall while still allowing access to documents.

Benefits for the developersÆ customers include:

• Reliable fast access to updated software.
• Fault-tolerant architecture provides service for mission-critical applications.
• Software that executes dramatically faster than applets.
• Software that is more powerful because it is not restricted.
• Being allowed to keep their browser set up as they want it without having to update (or backdate) in order to run a particular applet.

DSJ overview

There are two complementary components to DSJ: the DSJ server and the DSJ client.

The DSJ server stores Java classes in its internal database. DSJ supports different versions of the same class, so that different versions of an application are available at the same time, if desired. The server waits for service requests from a DSJ client.

The DSJ client software is installed on each client machine. The client software can be updated remotely by the DSJ server whenever future version become available, so the installation and configuration only has to be done once. The client is configured to look for a primary DSJ server. The connection is made with a custom long-term TCP/IP connection protocol (as opposed to the stateless HTTP protocol used for applets). When the connection is made, the DSJ client can request a list of applications that are available, or request a specific application up-front.

The DSJ client employs a custom Java class loader. To run an application, it looks for its classes "over the wire" from the DSJ server, instead of relying on classes being physically installed on the client machine. Because the connection protocol is specifically designed to send classes, it is faster than an applet, and you get full-fledged Java applications, not restricted applets. By default, the DSJ client also caches the classes on the client machine, so the next time the application is run, it comes up immediately; unless there is an updated version of the application; in which case, it can automatically download and use the new version. All this is transparent to the user.

For more detail on how the client works, see What happens on the client. For more detail on the server, see What happens on the server.

How this guide is organized

• DSJ Client describes the DSJ client, including how to install and run the client software. It is intended for less-technical users that are simply using the DSJ client, and includes troubleshooting tips and descriptions of errors that they may encounter.
• DSJ Server describes how to install the server, add applications, and all other server administration tasks.
• DSJ Developer covers the issues for a Java developer that is writing applications that will be deployed by DSJ.

Typographical conventions

The DSJ UserÆs Guide uses the following typographical conventions to help you distinguish among various elements:

• A monospaced font is used for file and path names, file contents, and commands that are typed at the command prompt. For example:
  • The file: dsj.properties
  • The command: dsjclient Welcome
• Italics are used for named property settings, such as DSJServer , VersionDate, and UserDatabaseManagerDirectory.

Borland developer support services

Borland offers developers high-quality support options. These include free services on the Internet, where you can search our extensive information base and connect with other users of Borland products. In addition to this basic level of support, you can choose from several categories of telephone support, ranging from support on installation of the Borland product to fee-based consultant-level support and detailed assistance.

To obtain pricing information for BorlandÆs developer support services, see our Web site, at http://www.borland.com/devsupport, or call Borland Assist at (800) 523-7070.