Issue Summary

Loading a Confluence page which has 20 or more pie chart gadgets and that is connected to a busy JIRA instance leads to failing to load some of those gadgets with the errors shown below.

JIRA does not find the temporary file created in JIRA_DATACENTER_SHARED_FOLDER\caches\charts and returns the error "File not found" to Confluence, however the temporary file is later created and not deleted as the operation trying to load the file had completed before.

Steps to Reproduce

1. Create a Confluence page with many pie chart gadgets (at least 20)
2. Connect the Confluence instance to the JIRA instance
    It is important to note that the load in the JIRA instance has to be high in order to reproduce the issue.
3. Load the Confluence page (which will request JIRA to generate the temporary images to show the pie chart)

Expected Results

All the resources in Jira are cleaned up.

Actual Results

• When loading the Confluence page some of the gadgets are not loading and the below error is shown.
  

*For those temporary files that are not shown in the Confluence page the below error is shown in the JIRA log files.

2018-02-02 04:37:54,779 http-nio-80-exec-36 WARN anonymous 277x91142x3 - 10.25.192.102,10.25.192.13 /charts [c.a.j.charts.jfreechart.DisplayChartServlet] File not found, returning 404 (filename='jfreechart-onetime-83880084426271604.png').

• The same file that is shown as file not found in the JIRA log file is later created in the JIRA shared folder and not deleted. (See highlighted examples below).

Workaround
see https://jira.atlassian.com/browse/JRASERVER-67481