JSys - A Simple Continuous System Simulator

JSys is a simple graphical package for simulating continuous dynamical systems. It was created for educational purposes for use in a first level undergraduate introduction to systems thinking for students of Information Technology and Information Systems. It is written in pure Java and is very simple to set up and use on a machine with Java 1.4 installed.

It has been created by Professor Grahame Cooper of the Information Systems Institute at the University of Salford in England. The work is copyright and is released as open source software under the Open Software License v. 2.1.

Some Screen Shots of JSys in action are available on a separate web page.

You may also view the API documentation here in Javadoc format.


The current version of JSys is version 0.1. This is a fully working version that has undergone some testing by the author.

You may download JSys here. Three files are available containing the executable package, the source code and the Javadoc API documentation respectively.

Third Party Libraries

JSys makes use of three java libraries to implement various parts of the functionality. The jar files containing these libraries are included in the JSys distribution zip file for convenience, but the source code may be downloaded from the following locations:

JHotdraw is used to implement the graphical user interface, including the block diagrams.

Java Mathematical Expression Parser (JEP) is used to evaluate mathematical expressions. This may be downloaded here.

PTPlot, from the Ptolemy project is used to create graphs of parameters against time.


Installation is simple if you already have Java 1.4 runtime installed and working on your machine. Simply unzip the zip file in a suitable location on your hard disc, and go to the folder jsys.

If you are working on MS Windows, then you can launch JSys by running the batch file jsys.bat.

If you are running on Linux, then you can launch JSys by running the batch file jsys.sh.

On any other platform, carry out the following commands:

Set the classpath to "./lib/jep-2.3.0.jar;./lib/jhotdraw.jar;./lib/plot.jar;./jsys.jar" or  the equivalent for your operating system.
Run the command: java org.jsyshome.jsys.JSys

A number of example models are included in the jsys folder.

Copyright (c) 2005 Grahame S Cooper - G.S.Cooper@salford.ac.uk

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