Summary

Unicode Control Code is crashing JIRA Gadget list.

Symptom

• When opening gadget list in JIRA, it shows empty.
• Log is filled with below

  /rest/config/1.0/directory.json [directory.internal.impl.DirectoryImpl] Could not retrieve directory entries from application-provided gadget specs: plugin gadget 'Key{pluginKey='com.pyxis.greenhopper.jira', location='gadgets/days-remaining.xml'}' failed validation
  -------------------------------------------------------------------
  2014-10-08 10:26:27,673 http-bio-8080-exec-2 WARN user 626x177724x1 1tmk3wu xxx.xxx.xxx.xxx,127.0.0.1 /rest/config/1.0/directory.json [directory.internal.impl.DirectoryImpl] Could not retrieve directory entries from application-provided gadget specs: null
  

Workaround (Done by @hgword1)

Remove Unicode Control Code from Language pack.

Resolution

Do Not accept Unicode Code Control character via IPT nor TAC.