code: public static void inject(final MavenProject project, final InputStream properties) throws MojoFailureException {
      final Properties defaults = PropertyUtils.loadProperties(properties);
      final NarProperties nar = getInstance(project);
      nar.properties.putAll(defaults);
    }
docs: Programmatically inject properties (and possibly overwrite existing
  properties)
  
  @param project
  the current maven project
  @param properties
  the properties from input stream