The following issue types are available in JBoss JIRA:
Feature Request - A new feature of the product, which has yet to be developed. Feature requests appear near the top of release notes. Blocker and Critical priorities mark the features that are appropriate to advertise in marketing material such as datasheets and sales presentations.
Patch can be used for performance enhancements, code refactoring and other optimization related tasks for existing functionality.
Bug is a problem which impairs or prevents the functions of the product.
Task should be used if none of the other categories seem appropriate.