Use a preparedStatement with a parameter on a 5 characters column.
When you execute the query (select, update, delete or insert), you don't obtain the same result if the length of the parameter value is over 5 or over 20 :
- Over 5 characters you obtain a FBSQLException
- Over 20 characters you obtain a DataTruncation
If the value contain 11 accented characters, the DataTruncation Exception is thrown.
I have attached a JUnit test case.