Running Java applets

Overview

Java is an exciting new application programming language. Java-coded applications, called applets, can be embedded in Web pages and then executed by the browser. This is particularly useful for processing intensive or time-sensitive elements of a Web page, like multimedia and animation.

You need a Java-enabled browser like the 32-bit version of Netscape Navigator 2.01 to run Java applets. Additionally, as Java applets are usually represented by filenames beyond the DOS 8.3 convention, Java applet files must be stored on a disk volume that supports long file names. The NetWare long name space module can be used to provide long filename support for Java applets.

As part of the standard NetWare install, the long name space support module (LONG.NAM) is installed on a NetWare server in the SYS:/SYSTEM directory. However, as there are memory and disk space requirements to consider when supporting long file names, the name space module is not automatically loaded or added to a volume. To support Java applets on the NetWare Web Server, you must set up long name space support.

Once you have set up long filename support, you can run the demonstration applet included with the Web Server.

Setting up long name space support

Each name space added to a volume requires additional server memory. If you add name space support to a volume and do not have enough memory, that volume cannot be mounted.

Use the following formula to calculate the additional memory required for each added name space on a volume:

0.032 x volume_size (in MB)/block_size(in KB)

Round to the next highest megabyte and verify that this memory is available.

For example, adding an long name space to a 100 MB volume with a block size of 4 KB would require 1 MB of additional memory, as shown:

0.032 x 100 MB / 4 = 0.8 MB

Once you have verified that the memory is available, set up long name space support as follows:

1. Verify that the LONG.NAM module exists in the SYS:SYSTEM directory and in the directory where NetWare is installed.
2. At the server console prompt, type

   LOAD LONG.NAM <Enter>
ADD NAME SPACE LONG TO volume_name <Enter>

   where volume_name is the volume on which to add name space support.

3. Use the Volumes command to display a list of the server's volumes and the name spaces supported and verify that the long name space has been added. Type

   VOLUMES <Enter>

NOTE: Once you have added a name space, the name space module autoloads each time the server comes up. As such, you only need to add a name space to a volume once, not each time the server comes up.

Running the demonstration applet

The Web Server includes a demonstration applet. A self-extracting file (WEB\DOCS\JAVADEMO\JAVADEMO.EXE) contains the demo applet files. To run the applet, it must be stored in your document tree on a volume that supports long filenames. To extract the file and run the demo

1. If you have not already done so, set up long name space support on the volume containing the JAVADEMO.EXE file.

2. Start Windows 95.

3. From a client workstation, map a drive to the Web Server volume containing the JAVADEMO.EXE file.

4. Select Run from the Start menu.

5. Type the drive letter, path, and filename of the JAVADEMO.EXE self-extracting file in the Run command line. For example, assuming G: is the mapped volume, type

   G:WEB\DOCS\JAVADEMO\JAVADEMO.EXE

   The applet files are extracted and the directory structure is set up appropriately.

6. Start your browser (Netscape Navigator 32-bit version).

7. Specify the following URL:

   http://hostname/javademo/javademo.htm

   where hostname is the DNS name or the IP address of the Web Server on which the applet resides.

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