Important points to be remembered while coding in user exits!

Below are very important points to be remembered while coding in user exits/customer exits/BADI etc.

1.     Never issue COMMIT/ROLLBACK or call function modules that does commit work (like mail sending FMs) in user exits.

2.     Never issue own Pop-Up using function modules. This will affect existing BDC programs

3.     Place the conditions so that your code will be executed only in particular case.

4.     Use own local work area instead of standard internal table header lines             

5.     Take care of performance tuning techniques.

6.     Use IF statement instead of CHECK (Only preferred in user exits)