Before you begin, make sure that you have at least following installed :

• Java runtime enviroment 1.4 or better installed
• A copy of wal.jar which you can download from http://www.sourceforge.net
• A copy of your appliction you want to bundle with WAL

To setting up your app for production, you need R/W access to a website of your choice.

Because WAL support only a subset of the JNLP Specification, there is not much to define.

A sample of a very minimalistic JNLP descriptor file

A sample of a standard JNLP descriptor file

For a poor (minimalistic) JNLP Descriptor you have at least to support the following

jnlp codebase	holds the URI of your application resources and your JNLP file.
jnlp href	is the name of your jnlp file.
jar href	is the name of the jar archive of your application.Use a jar tag for each additional application resource
main-class	is the name of the class from your application which holds the main method

First create a new directory (i.e c:\demo). Copy wal.jar and jnlp.jar into. With the argument -h (see below ) you can get some help about available options.

C:\demo>java -cp jnlp.jar;wal.jar; wal.Launch -h

Usage: java -jar wal.jar [-options]

-h Print this screen
-i Initializes WAL. Needs two additional arguments.
    codebase - where your app resides
    href     - name of your jnlp file
    i.e -i http://www.mysite.com/update myapp.jnlp
-l Print license information

Before you can use WAL, you have to initialize its cache directory. Therefore you have to start at least once WAL with the argument -i.
The option -i need to additional arguments. First the jnlp codebase and second the name of your created demo.jnlp file. Both must not exist at this time. It is just to tell WAL which application it should cover.

java -cp jnlp.jar;wal.jar; wal.Launch -i http://localhost/wal demo.jnlp

Wal successful initialized !

Now you can see a new created directory called cache and inside a jnlp file. Regard that this is not the jnlp file you created before. At this time this jnlp file stores only the information you supplied within the -i option.
So everything what resides in your created directory can now zipped or passed to an install tool.

As far you can see the whole setup package is smaller than 100k because it does not include your application at this time.

However you have the possibility to put your application jar into cache directory to prevent a increased launch time, when your application is started on client system for first time.

Finally transfer your application resources and your new written jnlp file to the location you defined before.

If you know start that application on a client system, the following should perform :

1. WAL checks for a new jnlp file on known codebase and href.
2. Because WAL have just a default jnlp file, it tries to download the jnlp file by codebase.
3. Resources which are defined in the jnlp resource tag, will be downloaded if that packages. not already exists within cache directory.
4. Finally the covered application will be launched