/**
  * Return configuration used to start up OSGi implementation.
  *
  * @return
  */
 private java.util.Map<String, String> prepareSettings() {
   java.util.Map<String, String> config = new java.util.HashMap<>();
   config.put("osgi.console", "");
   config.put("osgi.clean", "true");
   config.put("osgi.noShutdown", "true");
   // export packages
   config.put(
       org.osgi.framework.Constants.FRAMEWORK_SYSTEMPACKAGES_EXTRA,
       configuration.getPackagesToExpose());
   return config;
 }