config-prettyfaces/src/main/java/com/ocpsoft/pretty/PrettyContext.java
public void sendError(int code, String message, HttpServletResponse response)
   {
      Assert.notNull(response, "HttpServletResponse argument was null");
      try
      {
         if (message != null)
         {
            response.sendError(code, message);
         }
         else
         {
            response.sendError(code);
         }
      }
      catch (IOException e)
      {
         throw new IllegalStateException("Failed to send error code: " + code, e);
      }
   }
public void sendError(int code, String message, HttpServletResponse response)
   {
      Assert.notNull(response, "HttpServletResponse argument was null");
      try
      {
         if (message != null)
         {
            response.sendError(code, message);
         }
         else
         {
            response.sendError(code);
         }
      }
      catch (IOException e)
      {
         throw new IllegalStateException("Failed to send error code: " + code, e);
      }
   }
Sends an error response to the client using the specified HTTP status
code.

@param code the error status code
@param message the descriptive message
@param response
@see HttpServletResponse#sendError(int, String)