Mylyn is a wonderful Eclipse plugin focused on helping you work more effectively by connecting the IDE to the issue tracker. As their web-site says, Mylyn “reduces information overload and makes multi-tasking easy… by making tasks a first class part of Eclipse, and integrating rich and offline editing for repositories such as Bugzilla, Trac, and Jira.”
Mylyn brings Jira right inside your IDE. You can view your whole list of assigned issues in Jira. If you tell Mylyn which issue your working on, it will remember everything you do in conjunction with that issue. It begins to hide away all the extraneous stuff that does matter right now, allowing you to focus on what does.
If you need to change tasks, just let Mylyn know and it will save your context. When you’re ready to come back, Mylyn will bring back all of the files, views and and jobs associated with your task, letting you pick up right where you left off.
What’s more, Mylyn provides the ability to edit and comment on Jira issues right from the IDE, whether you are online or offline. Mylyn handles syncing up any changes you make to Jira when you come back online.
Take a look at the screenshot that illustrates all of this:

  1. In the left pane, the Package Explorer is showing only the subset of the system related to the
    active task, called the task context. This helps reduce information
    overload and makes multitasking a single-click operations.
  2. In the middle pane, the rich editor for Jira issues supports instant open, offline access and
    editing, drag-and-drop attachment, task context sharing, and hyperlinking to
    source code and issues. This helps you code in a task-focused way without
    breaking your workflow.
  3. In the left pane, the Task List integrates filters and highlights incoming changes. This
    allows you to de-clutter your inbox from email notifications.
  4. Mylyn automatically groups incoming and outgoing changes by task and
    links commit comments to issues. This facilitates committing and tracking

You can learn more about all these features at:

Atlassian has been working with the Tasktop team for the last few months to improve the integration between Mylyn and Jira, and you can now download and install the Mylyn/JIRA connector for Eclipse here. The Mylyn 2.2 release is scheduled for December 19th and will include additional improvements to the Jira Connector. To help us prioritize work for 2.2 and future releases, please let us know what you think!”

Using Jira in Eclipse with Mylyn