JESS is implemented in Java, whereas CLIPS is in C.

You can search on Google "JESS download"   or  "JESS expert system download" to find where to download it from.
Or, download it from here (it might be expired, see below)
     http://staff.fmi.uvt.ro/~horia.popa/JESS

It will require a registration, then you can get a 30 days available software. After 30 days you can download it again, and so on,
using your registration.

UPDATE 1: the file you can download from the Internet or from my location is Jess71p2.zip For some reasons, the Internet location does not work 
temporarily, and the local copy  is already expired. So we will instead GO TO Step 6-B)

UPDATE 2: There is also the file http://staff.fmi.uvt.ro/~horia.popa/Jess71a1.zip  which I found at this location http://alvarestech.com/temp/fuzzyjess/Jess60/ 
which seems to work using steps 2) to 12)

Step 2) After downloading, you will extract the archive. 
Step 3) Then go to the Eclipse folder. There are 4-5 archives there.
Step 4) Unzip those archives. You will need to get 2 folders "features" and "plugins"
Step 5) Locate your instalation of Eclipse (I've tested them on the JUNO distribution, on others it might not work)
Step 6) Copy the 2 folders obtained at step 4 into your Eclipse base foolder. E.g. on my computer this is "c:\Eclipse"
Step 6A) Go to step 7)

Step 6-B) Alternate solution when downloading does not work. Copy somewhere the file jess.jar that you can donload from 
	http://staff.fmi.uvt.ro/~horia.popa/JESS
It belongs to an older Jess distribution that comes with the "Jess in Action" (book) which you can ALSO find in the 
	http://staff.fmi.uvt.ro/~horia.popa/Jess in Action
folder. That distribution expires in 1 year (not in 1 month).
Then indicate it (the file jess.jar)  to Eclipse in your project as "external jar" following the steps described in 11) and 12). Be carefull that before these 2 steps you also need to do the steps 7-10). So continue with step 7 having in mind that at step 11 you will add as external jar the file indicated here (jess.jar) and not the ones indicated there (from the lib folder).

Instalation is complete

Step 7) Start Eclipse. Create a project called "testjess" as "Java Project"    (any name will do)
Step 8) Right click on the project name and say "new file". Name you file "61.clp"   (any name will do, but the extension has to be CLP)
Step 9) Write your expert system there, e.g. copy the following just to test it

	(defrule print-it
		=>
	(printout t "Hello World")
	)
	
	(reset)
	(run)

Step 10) Press the run button in Eclipse. You will get your Hello World message



If it doesn't work, then we need to tell Eclipse where to find the *.jar for JESS and also the name of our program (CLP file)

So, the following steps are to use ONLY if until Step 10 we didn't obtain the desired effect.
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Additional steps:

11) Right click on the project -> Project build path -> add the 2 .jar files from the lib folder from wherever you unzipped 
JESS as "External jar"

12) Right click on 61.clp -> Run configurations -> double click on "Java application" (it will create a new run configuration) ->
Specify the main class -> Main.jess -> Arguments -> src/61.clp

Additional steps (var 2)

11-A) move 61.clp from the src subfolder directly in the project folder (one level up, in the parent directory of src).
12-A) run the project again (it might work, haven't tested it yet myself) 






Exercise, when the simple example works:

From Lecture 8, on slide 5 you have an example with 2 files, a java class and an simple expert system. Try it!
Note: if oyu used the first variant with additional steps, then modify in step 2, where it says src/61.clp"  änd
put the name of your new .CLP file (e.g. src/easy_java.clp)


Here is the normal end of this file!
--------------------------------------------

Step 11) Alternate way to install Jess: copy somewhere the file jess.jar