if (impl == null) throw new IOException ("Cannot initialize Socket implementation");
SecurityManager sm = System.getSecurityManager(); if (sm != null) sm.checkListen(impl.getLocalPort());
  public Socket accept () throws IOException  {    if (impl == null)      throw new IOException ("Cannot initialize Socket implementation");    SecurityManager sm = System.getSecurityManager ();    if (sm != null)      sm.checkListen (impl.getLocalPort ());    Socket s = new Socket();    implAccept (s);    return s;  }