code: private boolean isWebstartAvailable() {
  		try {
  			Class.forName("javax.jnlp.ServiceManager");
  			// this causes to go and see if the service is available
  			ServiceManager.lookup("javax.jnlp.PersistenceService");
  			Log.info("Webstart detected using Muffins");
  		} catch (Exception e) {
  			Log.info("Using Local File System");
  			return false;
  		}
  		return true;
  	}
docs: Quick test to see if running through Java webstart
  
  @return True if jws running