Rapid Design: 

Programming with the Display Machine needs no GUI programming skills at all. The Programmer has to know Java and the application. Not more. His task is to write well structured application classes. We call this types of classes a "virtual machine". When a project is started, it is even enough to create the class frames with routines and variables - no need to fill in any code. Then the Display Machine takes over. With the help of drag & drop commands and variables are moved to the canvas and automatically translated into buttons, fields, pull down lists and much more .. its like magic.

From time to time - when there is no way around - it is necessary to put real code into the classes (especially when the program is supposed to do some real work). But you can immediately use the freshly created code (and test it). And, when your classes are ready, you can reuse them in a different project the next day. Within some time your knowledge is collected in "knowledge class systems" ready to be used im many different projects.

A general ledger class system (for example) contains plenty of knowledge about accounting. Only "frozen" knowledge formulated in Java - but no user interactions. Then the DisplayMachine comes in. Programming is now

• using drag & drop - really based on a graphical system
• based on a well crafted general ledger "virtual machine"

As mentioned above one can write two or more different systems based on ONE virtual machine. They look completely different and behave also different. Both do accounting and both use the same "machine".

This is similar as programming other virtual machines: The JVM (Java virtual Machine) works similar. It is written in order to run Java programs. But most Java applications use this virtual machine translating the JVM commands to some machine code.

Our General Ledger written with the Display Machine code is located at a much higher level:

• It is written for an "Accounting Virtual Machine" (AVM) as class package in in Java
• which is itself executed with the help of the JVM mentioned above
• which is executed with the help of machine code.

The Display Machine

• frees the programmer totally from the tedious job of GUI programming
• separates application and visualisation
• creates maintainable and compact programs