System system = (System) getChildItem(ext);
System system = (System) getChild(ext);
    public void shutdownSystem() throws Exception {        //?? The system where the signal is coming from needs to be found        //?? (e.g. check on which gui the mouse click occured).        //?? This system reference will be sent as subject of the signal.        String ext = new String(Launcher.SYSTEM.getJavaObject() + "_" + java.lang.String.valueOf("0"));        System system = (System) getChildItem(ext);        // The system can be null if another launcher was used to create it.                if (system != null) {            // Remove and destroy the system the signal is coming from.            removeSystem(ext);            destroyChildItem(system);            // If this launcher system has sent the exit signal, then set the            // shutdown flag causing the waiting loop to break and by this to            // finally exit the whole java virtual machine.            setChildItem(Launcher.SHUTDOWN_FLAG, new Boolean(Boolean.TRUE));        } else {            // The system is null which means that it was created by another launcher            // and now has to be shut down using a socket connection.            // (This launcher has probably been started in an extra process,            // by another shell/batch script, e.g. a special shutdown script.)//??            handle(new String(""), Launcher.SHUTDOWN_SYSTEM_ACROSS_SOCKET_ACTION, new Boolean(Boolean.TRUE));            shutdownSystemAcrossSocket();        }    }