How to instantiate a .class from a JSP?

Hi,
probably it's a simple problem, byt I'm new in JSP and I couldn't work it out.
I'm converting a SSJS Netscape Application to JSP. My needing is to write a Java .class containing only static methods, to call them from the JSP pages.
For trying, I wrote a simple class that I call from a JSP page, but I get this error:
Error: 500
Location: /JSP24H/cap01/Simple2.jsp
Internal Servlet Error:
org.apache.jasper.JasperException: Unable to compile class for
JSPC:\tomcat\work\localhost_8080%2FJSP24H\_0002fcap_00030_00031_0002fSimple_00032_0002ejspSimple2_jsp_0.java:80:
Incompatible type for =. Can't convert void to java.lang.String.
v = GenFunction.messaggio();
^
This is the JSP instantiating the Java class:
<HTML>
<HEAD><TITLE>A Simple JSP</TITLE></HEAD>
<BODY>
<FONT COLOR="blue" FACE="Trebuchet">
<CENTER>
<%@ page import = "GenFunction" %>
<% out.println("My name is Charly !" + "<br>"); %>
<%
String v = " ";
v = GenFunction.messaggio();
out.println( v );
%>
</CENTER>
</FONT>
</BODY>
</HTML>
And this is the class instantiated from JSP:
public class GenFunction {
public static void main (String args[]) {
public static String messaggio() {
String a;
a = " Hello world !";
return a;
In order to be sure about what I'm doing, I opened a DOS window and I called the class within the following:
public class call_Class {
public static void main (String args[])
String v;
GenFunction x = new GenFunction();
v = x.messaggio();
System.out.println(v);
When I instantiate the class from DOS it's all right, why not from JSP. It seems to be returning a void value (I tried with casting too but without success).
Thanks !

Do you have multiple versions of classes in the server CLASSPATH somehwhere? If you have changed the class, and not bounced the server, try bouncing the server(may be using cached class)
-Mak

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