Class, JAR and Cab files.

This section is intended to give an explanation of the files which make up the Advanced Menu Bar.

Class files.

These are the compiled java code files. They contain all the machine instructions which make up the applet program. It is these instructions, which are interpreted by the Java Virtual Machine contained within your browser, which provide all the functionality of the applet.
You will also notice that most of the class files are within the Neutron Solutions Limited - menubar directory and yet more within the netscape - javascript directory. Each class file can be thought of as little sub-program and each one provides a little piece of the functionality which makes up the complete applet. For ease of maintainability and futre upgrade we organise this functionality into the directories that you see. The top level class (MenubarApplet.class) contains instructions which tell your browser where to find all the sub-classes which make up the complete applet. It is therefore vital that when either installing on your local machine or your web server that this directory structure is kept in tact.
(Please note: File names and Directory names are case sensitive).

JAR File.

The jar file ( AdvMenubar.jar ) is like a zip file which contains all of the above the class files in the correct directory structure. A browser will download the jar file and then extract all of the above classes into it's memory and because the jar file is generally about half the size of the sum of all the class files, this improves online download speed dramatically. A JAR file can be used by all the recent browser versions ( for IE and Netscape this generally means version 3.x and upwards ).

Cab File.

The Cab file ( is like the JAR in that is a zipped up version of all the class files in their correct directory structure, with one important addition - Our Code Signature (more about this in a moment). Unlike JAR files, Cab files can only be used by Internet Explorer (which at the time of writing represents about 80% of web users). It is for this reason that we say you should upload both the JAR and the CAB files to your web server. In this way your user's who run IE will automatically download the CAB file, whilst your user's running netscape will automatically download the JAR file. This is all automatic and completely transaparent to you and your web site visitors.

So if IE can use the JAR file why bother with the Cab file ?

The latest IE browsers ( version 5 and up) add a little message ("warning applet window") at the bottom of every new window that an applet creates. As I am sure you will agree this can make a perfectly nice menu system look very ugly indeed. However we have gone to a great deal of trouble and expense to overcome this and at no additional cost to you our customer. As professional software developers we have applied for and been granted a Digital ID which enables us to digitally sign our code (for more information on this process please see It this Digital ID with which we have signed & certified the Cab file. This means that our code can run as 'trusted' by Internet Explorer and as such the ugly warning message is not displayed on the pop up window's of the menu.

So if Netscape is going to get all the applet code from the JAR file and IE is going to use it all from the CAB file, why load up all the individual class files and directories to the web server ?

Whenever Internet Explorer encounters a piece of code signed with a genuine certificate it will inform the user and ask them to confirm that they wish to trust code from this publisher (ie. ourselves). This dialogue occurs once upon the first load of the applet. At this time the user has the opportunity to tell IE to always trust code with this certificate, which if they do, then this dialog will never appear again for any code signed by ourselves. If the user answers "no" to this dialog then IE will refuse to use the Cab file and will instead look for the class files. So for your few users who choose not to answer yes it is important to have the class files available from your web server.

If you require any further information on this or any other aspect of the Advanced Menu Bar then please do not hesitate to contact us at,

Security Warning Dialogue
This applet has been signed by a professional software developers certificate. As such in some browser versions a security warning dialogue may initially pop up informing the user of this fact. This has been necessary so that the sub-menu windows do not contain the "warning applet window" message.
We realise that for some implementations this situation may not be acceptable and as such we have developed a second range of menu applets which do not contain this dialogue. If graphic functionality on the sub-menu's is not important for your implementation then please also see our range of AWT menu's at,