There is an additional library for Tomcat that allows for optimal performance, namely additional OS functionality and the ability for Tomcat to handle OpenSSL certificates. From Apache:

Tomcat can use the Apache Portable Runtime to provide superior scalability, performance, and better integration with native server technologies. The Apache Portable Runtime is a highly portable library that is at the heart of Apache HTTP Server 2.x. APR has many uses, including access to advanced IO functionality (such as sendfile, epoll and OpenSSL), OS level functionality (random number generation, system status, etc), and native process handling (shared memory, NT pipes and Unix sockets).

Please include this by default in our Tomcat standalone installations - OpenSSL certificates are much easier to handle than JKS.

If it's not configured, the below error message will appear:

INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /Users/dcurrie/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.

There is no negative side effects to not having this installed - it's simply an info message.

Workaround

 A forewarning disclaimer:
This workaround includes steps to customize or extend Atlassian software (adding/changing CSS rules, HTML, JavaScript, etc.). Per the Atlassian Support Offerings, support does not include customizations made to Atlassian products. Be aware that this material is provided for your information only and using it is done so at your risk.

If you have any questions about this or any customization, please ask the community at Atlassian Answers or consider working with an Atlassian Solution Partner.

Here's the actual workaround:
A non stock APR can be installed as per https://tomcat.apache.org/tomcat-7.0-doc/apr.html.