The following  segment works on windows/mac & linux and has been in use for
over 2 years in our office

Fairly easily, basically I use it for deploying updates.
I have a class called "bootloader" that contains the following,  the most
important thin is that  your "bootloader" class MUST NOT link into any of
your other libraries. (if it does then the JVM goes on a class hunt trying to
resolve all other classes & preload them)

That allows you to use the bootloader to auto update any other files , other
than "bootloader"

OurJarClassPathArray, holds that paths of any jars you may need (libraries,
DO NOT HARDCODE, or use  imports)

loadThisClass , holds the class you want to run

 final Method mainMethod;
       final Class toRun;

 ClassLoader loader = new URLClassLoader(OurJarClassPathArray);
      toRun = loader.loadClass(loadThisClass);
     mainMethod = findMain(toRun, thisargs);

    if ((mainMethod != null)) {
               //launch the new program in a new thread so we can exit the
bootloader (can we really?)
               mainThread =
                   new Runnable() {
                           public void run() {
                               try {
                                   final String[] dummy = null;
                                   mainMethod.invoke(null,
                                       new Object[] { dummy });
                               } catch (Exception e) {
                                   System.out.println(
                                       "Exception Caused when trying to
Execute main Class");
                                   e.printStackTrace();
                               }
                           }
                       };
                       //this appears to be important code that was stopping
the sh.t
                       //running on the linux correctly, specifically the
classloader.
               Thread mainRunner=new Thread(mainThread);
             mainRunner.setContextClassLoader(loader );
              mainRunner.start();
System.out.println("We think have exited the BootLoader ");
       System.gc();

Why not instantiate the new instance directly
from the code in the original instance?  E.G.

class Application {
...
  public void actionPerformed(ActionEvent ae) {
    if (...) {
      Application app = new Application();
   } else if ....

Andrew T.