secure java web application

Question
How do I secure my web application for java Tomcat ?

Answer
Here's a link that shows how to set up app security with Tomcat
http://www.avajava.com/tutorials/categories/tomcat

If you need more background on Java EE web security, here's another good reference.
https://docs.oracle.com/javaee/7/tutorial/security-webtier.htm#BNCAS