boolean mandatory_firstName = (first_Name != null && !first_Name.isEmpty() && !first_Name.trim().isEmpty());
boolean mandatory_lastName = (last_Name != null && !last_Name.isEmpty() && !last_Name.trim().isEmpty());
boolean mandatory_userName = (user_Name != null && !user_Name.isEmpty() && !user_Name.trim().isEmpty());
boolean mandatory_Password = (Pass != null && !Pass.isEmpty() && !Pass.trim().isEmpty());
boolean mandatory_ConfPass = (Confirm_Pass != null && !Confirm_Pass.isEmpty() && !Confirm_Pass.trim().isEmpty());

if((mandatory_firstName || mandatory_lastName || mandatory_userName || mandatory_Password || mandatory_ConfPass) == false)
    {
        Assert.fail("One of the mandatory fields is missing text.");
    }