The code was compiled with Java 2 - version 1.4.2 (03), so you will definitely need that version as some of my friends have tried 1.3 and it didn't work.
If you want it (Java 2 - version 1.4.2 - 03) and don't have it, here is the link to the general downloads page: http://javashoplm.sun.com/ECom/docs/Welcome.jsp?StoreId=22&PartDetailId=j2sdk-1.4.2_04-oth-JPR&SiteId=JSC&TransactionId=noregYou only need the JRE (Java run-time environment - about 12 megs), but feel free to grab the SDK (Software Development Kit - just under 40 megs) if you want to develop using Java 2 version 1.4.2 (03)
and here is the general info (i.e. documentation) on this version of Java:
http://java.sun.com/j2se/1.4.2/docs/index.html
Once, you have installed the JRE or the Java SDK the jar file (InfoFinder.jar) has been set, so that you can either just double click or click on the file (once you have JRE or the Java SDK installed) and the program will run. Otherwise, if you would rather start it from the command prompt:
java -jar InfoFinder.jar