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.
As you indicate you will be using Tomcat, your best bet is to use container-managed connection pooling. Tomcat provides this using DBCP. The details are Tomcat-specific, so I've moved this post to the Tomcat forum.