skip DTD validation

http://stackoverflow.com/questions/243728/how-to-disable-dtd-at-runtime-in-javas-xpath

DAO

http://www.ibm.com/developerworks/library/j-dao/

http://java.sun.com/blueprints/patterns/DAO.html

java tip

http://www.javaspecialists.eu/archive/Issue142.html

http://www.1001javatips.com/