I have seen this twice.

Upon the first start-up after upgrading from 2.7.2-rc4 to 2.8.0-m1, the log stops at the following line and the Crowd server does not proceed to finish the start-up:

2014-05-22 06:24:51,769 localhost-startStop-1 INFO [atlassian.plugin.manager.DefaultPluginManager] Plugin system started in 0:00:11.075
2014-05-22 06:24:51,789 localhost-startStop-1 INFO [ContainerBase.[Catalina].[localhost].[/crowd]] org.tuckey.web.filters.urlrewrite.UrlRewriteFilter INFO: loaded (conf ok)

If accessing the Crowd Console, I will see an error screen saying:

fatal Error while trying to initialise Crowd Container. could not perform addBatch

(See attached the screenshot and the complete log).

I needed to restart once or twice to get the Crowd Server completely started. (For one occurrence of the issue, I only needed to restart once; for another time, I needed to restart twice.)