Uploading or Updating Plugins does not work in JIRA 7.1.0 after a fresh installation on first boot. Add-ons can not be installed on first startup of a JIRA Instance. Restarting the instance fixes the problem.
The browser reports the following error:
"An error occurred during installation. Refer to the logs for more information."
The following WARN log entry may be present in atlassian-jira.log
Attempt to update or install a new Add-on through the UPM (Universal Plugin Manager)
Attempt to install an Add-on Such as JIRA Software or JIRA Service Desk from Application Administration.
Otherwise, attempt to update or install a new Add-on through the Application:
When an add-on is installed, the plugin should be available and reported as installed and running.
When the add-on is installed, the files are downloaded, but then a "PluginInstallException" is thrown reporting: "Failed to install OBR jar artifact".
Restart The JIRA Instance. This will automatically install any plugins that failed to install successfully.
After Restarting the JIRA Instance, future Add-ons will install successfully.