to avoid locking other threads.

Change-Id: I58ca413df8daed8de2de4f93053fb6181e12d8f7
Signed-off-by: Joerg Kubitz <jkubitz-eclipse@gmx.de>
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.ui/+/186656
Tested-by: JDT Bot <jdt-bot@eclipse.org>
Reviewed-by: Jeff Johnston <jjohnstn@redhat.com>