if ((username != null && username !="") || (password != null && password !=""))
if ((username != null && !username.equals("")) || (password != null && !password.equals("")))
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException  {    String  password=null, username=null;     Integer userId=null;        sp = new ServletPrinter(response, "About me");    username = request.getParameter("nickname");    password = request.getParameter("password");        // Authenticate the user    if ((username != null && username !="") || (password != null && password !=""))    {      try      {        initialContext = new InitialContext();      }       catch (Exception e)       {        printError("Cannot get initial context for JNDI: " + e+"<br>");        return ;      }     }    else    {      printError(" You must provide valid username and password.");      return ;    }    sp.printHTMLheader("RUBiS: About Me");    SB_AboutMeHome aboutMeHome;    SB_AboutMe aboutMe;    try     {      aboutMeHome = (SB_AboutMeHome)PortableRemoteObject.narrow(initialContext.lookup("SB_AboutMeHome"),                                                                SB_AboutMeHome.class);      aboutMe = aboutMeHome.create();    }     catch (Exception e)    {      printError("Cannot lookup SB_AboutMe: " +e+"<br>");      return ;    }    String html;    try     {      html = aboutMe.getAboutMe(username, password);       sp.printHTML(html);     }      catch (Exception e)     {       printError("Cannot retrieve information about you: " +e+"<br>");       return ;     }    sp.printHTMLfooter();  }