Having an issue with errors on a livecycle project, can anyone tell me what's wrong?

Question

Hello! I've uploaded screenshots of the errors here : http://imgur.com/a/0mKtU
When you click the add button to add another column, the column appears (exactly how it should) but then this error comes up. I don't know much about any of this, but I think it's because there's something extra that shouldn't be in the code? Can anyone confirm for me or give me an answer on this? I feel like it's simple but I have little to no experience with livecycle.
Thank you for your time and help!
This is the code for the Oplus1Table:
form1.#pageSet[0].Page1.WitnessTable.AddWitness::click - (JavaScript, client)
WitnessTable.Witness1.instanceManager.addInstance(1);
And the Errors:
Script failed (language is formcalc; context is xfa[0].form[0].form1[0].#pageSet[0].Page2[0].Oplus1Table[0].Oplus1Table[0].Oplus1[2])
script=...
Error: accessor 'true' is unknown
and this is the code for the WitnessTable:
form1.#subform[0].WitnessTable.AddWitness::click - (JavaScript, client)
WitnessTable.Witness1.instanceManager.addInstance(1);
And the Error
Script failed (language is formcalc; context is xfa[0].form[0].form1[0].#pageSet[0].Page1[0].WitnessTable[0].WitnessTable[0].Witness1[3])
script=...
Error: accessor 'true' is unknown
Like I said, I don't know much, but it looks to be the same error just in different context based off of the Oplus1Table for the first error and WitnessTable for the next.
Thanks again for any help.

Answer 1

Hi Steven,
}catch (ClassNotFoundException ex)
catch(InstantiationException ix)
catch(IllegalAccessException lx)
try{
               //can use URL + dbName here
con =
DriverManager.getConnection("jdbc:mysql://localhost:33
06/dbName",user, password);
}catch(SQLException sqx)
{}For each of the catch block above, you should log the caught exception. This is also why you don't see any exception logged when errors occur.
There could potentially be a long duration between servlet.init() and servlet.doPost(). So, the connection that you establish during init() may be disconnected by timeout or other means by the time the code in doPost() uses "con" . Your code does not have any mechanism for recovering a failed connection.
Suggestions:
1) log exceptions
2) use a container managed JDBC connection pool
3) post in the correct forum (Application Server)