code: private static void propagateProperties(
        final Collection<String> vargs, final boolean copyNull, final String... propNames) {
      for (final String propName : propNames) {
        final String propValue = System.getProperty(propName);
        if (propValue == null || propValue.isEmpty()) {
          if (copyNull) {
            vargs.add("-D" + propName);
          }
        } else {
          vargs.add(String.format("-D%s=%s", propName, propValue));
        }
      }
    }
docs: Pass values of the properties specified in the propNames array as <code>-D...</code>
  command line parameters. Currently used only to pass logging configuration to child JVMs processes.
  
  @param vargs     List of command line parameters to append to.
  @param copyNull  create an empty parameter if the property is missing in current process.
  @param propNames property names.