pr = new SelectorProviderImpl ();
String propertyValue = System.getProperty("java.nio.channels.spi.SelectorProvider");  if (propertyValue == null || propertyValue.equals("")) systemDefaultProvider = new SelectorProviderImpl(); else { try { systemDefaultProvider = (SelectorProvider) Class.forName(propertyValue) .newInstance(); } catch (Exception e) { System.err.println("Could not instantiate class: " + propertyValue); systemDefaultProvider = new SelectorProviderImpl(); } }
  public static SelectorProvider provider ()  {    if (pr == null)      {        pr = new SelectorProviderImpl ();      }        return pr;  }