Description
public Iterator<Long> search has a synchronization on the Boolean 'done'
https://builds.apache.org/view/G-L/view/James/job/mailbox-site/site/apache-james-mailbox-store/findbugs.html#org.apache.james.mailbox.store.search.LazyMessageSearchIndex
See
http://findbugs.sourceforge.net/bugDescriptions.html#DL_SYNCHRONIZATION_ON_BOOLEAN
https://www.securecoding.cert.org/confluence/display/java/LCK01-J.+Do+not+synchronize+on+objects+that+may+be+reused