I see. I actually tried compiling this Parser.java file and got errors. So this made me wonder if these files are even meant to be compiled.

I can import java.lang.System without  a problem, and System is not a .class file but a .java file. In other words, .java files are imported into Jython without a problem here. Then, why doesn't this work for the parser? Why do I need a .class file to import it in the case of the parser?

And what is the role of adding the .jar file to the sys.path? Can you import without a class file if you do this? I am really terribly confused.