use java.lang.reflect in a soket server that accepts main class definition from
a
port.

ex:
- u'll send "LOAD com.filika.project.runner.Runner" from soket to your server
program
- server program  'll find the main class and loads it to its vm that running
with the
help of reflect package.
- and also u can send more initial parameters with reflect ->more at:
java.sun.com

or u can define a generic interface like

public interface MyLoadable{
public void load() throws Exception;
public void start()throws Exception;
public void stop()throws Exception;
public void unload()throws Exception;

}

than u can create your apllications using this interface, making a little
expansion
to the example above.