jenkinsci/jenkins — pull request #989 by recampbell (2013-10-28 19:54:09+00:00)
Title: [FIXES JENKINS-19622] Allow background tasks to run simultaneously, preventing task blockage

Deprecate hudson.model.Trigger#timer in favor of jenkins.util.Timer which exposes a ScheduledExecutorService. Up to 10 additional threads will be created to run pending tasks even if running tasks are blocked.

Also, move static initialization of timers to those components which require them.