This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
NULL POINTER EXCEPTION ,, that is your providing response to client ,, and information is NOT RECEIVE by the client ..
check out your code where you are providing final output to client.. the name of the variable whose information you want to be visible to your client,, maches the name of the variable in ABOVE CODE you have store the information..
Without being able to run your code, my best guess is that you are not getting a resultset back on line 70, but it's not obvious to me why. I would set a breakpoint just prior to that line and debug into it to see what's going on.