Some of the bags i have found are:

the response time was so slow for the system, this was 
because they were using String class for strong an object 
which needs string manipulation .

Solution:USE stringBuilder class which is mutable string.

When the user enters data and closes the button the data 
was added to the database which should'nt be.


When the user clicks save button twice error was displayed 
data already added 

Solution:Disable save button after click.