I don't know JGRASP but I can say that you haven't got your classpath right yet.

I suggest that you review
<http://java.sun.com/docs/books/tutorial/java/package/index.html>
and either
<http://java.sun.com/javase/6/docs/technotes/tools/solaris/javac.html>
or
<http://java.sun.com/javase/6/docs/technotes/tools/windows/javac.html>
as appropriate to your situation.  (Linux is like Solaris.)

Then study
<http://java.sun.com/j2se/1.5.0/docs/tooldocs/solaris/classpath.html>
or
<http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/classpath.html>
as the case may be.

In the spirit of exactness imposed by computers and computer languages, I
advise that the language is spelled "Java".

see http://mindprod.com/jgloss/package.html
http://mindprod.com/jgloss/classpath.html

Also read the installation instructions for JGrasp.  It looks as
though you left something out.

You can use "Settings" / "PATH/CLASSPATH" in jGRASP to add
classpaths to either the project or workspace. If this library is in a
jar file, add the jar file; otherwise, add the directory containing "edu".