A: 

Without doing a thorough analysis of your code, one thing jumps out:

Timestamp format must be yyyy-mm-dd hh:mm:ss[.fffffffff]

That's not what your arguments look like

Jim Garrison
Right. If I send a formatted string yyyy-mm-dd 00:00:01, the error says that 00 couldn't be understood. That's exactly why I'm asking what should I send and how. Thanks :)
Alfabravo
A: 

Have the web service bind the string to a date before passing it back. You want to do this, because it'll validate proper format and type. Binding and validating is necessary to avoid SQL injection as well.

duffymo
+1  A: 

Consider refactoring your code to handle dates as java.sql.Date objects instead of Strings. This will allow you to call setDate(....) instead of setString(...), and make your code cleaner.

http://java.sun.com/javase/6/docs/api/java/sql/PreparedStatement.html#setDate%28int,%20java.sql.Date%29

Thorbjørn Ravn Andersen
I've done so. When recreating the web service from the class -in Eclipse-, it raises a warning abput compliance with standards, which I ignored for the sake of testing... and looks like it works. In about five or six hours I probably will set this thread as solved
Alfabravo