A wide range of customizations can be done through the configuration of out of the box custom fields without adding any lines of codes. New fields can be added from a variety of field types for example and configured through the administration interface.

Where standard fields do not suffice, administrators can add as many 3rd party or self-developed custom fields as desired for specific issue types, in specific projects, etc. There is a large ecosystem of Add-on and customization developers and Atlassian supports these efforts with online and offline community infrastructure and events and documentation.

Custom code is developed in Java for which skilled resources are readily available in the market place. Also, most customization would be integrated using the Add-on framework which makes upgrading a customized instance a lot easier than with traditional enterprise applications.

Showcase Integration with: Atlassian Plugin Exchange, Jira API, Java Source Code

Steps to demonstrate

The best way to demonstrate the out-of-the-box customization capabilities is to visit Add-on Exchange and browse for Add-ons of interest. For a demonstration, there are many freely available Add-ons that can.

For an example how to install the calendar Add-on, see Installing Marketplace apps.

Demonstration requirements

Your Jira instance needs to be authorized with Atlassian (License Key) to be able to access Add-on Exchange. Also, you need to have access to the Atlassian servers from your Jira instance (internet connection / firewall permission).

Demonstration on Jira.Atlassian.com

Although end users are not authorized to install Add-ons on Jira.atlassian.com, many 3rd party gadgets are available on the instance. For example:

1. Create a new dashboard and name it 'Add-ons'
2. Add a new gadget and click on 'Other'.
3. Review and add 3rd party Add-ons such as the 'Remember the Milk' gadget or the Tree Frog.

Further documentation

http://confluence.atlassian.com/display/Jira/Adding+a+Custom+Field