DWR's Method Signature

JS client side

 SecPasswordChecker.preLoginCheck (name, password, callback);    

Java server side

public String preLoginCheck (String userName, String password, ServletContext servletContext) {..}

The method signatures of DWR method on Javascript side and server side are not equivalent. JS side declare callback whereas server side allows us to add HTTP servlet object (i.e. HttpServletRequest, HttpServletResponse, HttpSession, ServletContext or ServletConfig) declared on your method. DWR will not include it on the generated stub and upon a call of the method it will fill it in automatically.