dynamic java

Hi all,
what i'm trying to do is execute some simple java code dynamically from a jsp page and display output into this page.
I need to load a java program (this one should contain a main() method) and run this program. get output from this program.. and then display result to jsp page. for example :
test.java
---------
public class Test{
public static void main(String[] arg){
System.out.println("hello");
}
}
----------------
now from a servlet /jsp page i should run test.java which will display "hello" ...i.e "hello" should be displayed to the webbrowser in the jsp page. (should be done for any java program dynamically)

any Ideas on how to tackle this problem ?
thanking you.

If you must call them via the OS, look at Runtime.exec:
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Runtime.html

Why wouldn't you want to just instanciate the objects and call their methods?

Doesn't work that way. When you activate a separate Java program, it will send its output to System.out like any other Java program.

Since you're already in a JSP page, why the need for a separate program?

thanks for replying...
i'm developing a web application for online compilation and execution of java programs...user clicks a button and a java program should compile and execute...the problem is that my java progs sends output to System.out ..but i want to be able to get this output and display it into my web page...i suspect this involves using some technique to redirect output depending on which Thread is currently running.

I would appreciate any Help to solve this issue.

thanks.