...

/var/cache/tomcat5/work/Catalina/localhost/xmlui/cache-dir
/var/lib/tomcat6/work/Catalina/localhost/_/cache-dir
/opt/tomcat6/work/Catalina/localhost/xmlui/cache-dir
/usr/local/tomcat6/work/Catalina/localhost/xmlui/cache-dir

I changed access restrictions on a collections, but restrictions didn't change on its items

You have to remember that access restrictions are inherited from its parent collection only when items are submitted, not when access restrictions are modified. So the new items submitted to that collection will have the collection's restrictions you set, but existing items will keep their current permissions.

In other words: "When a new item gets archived in the repository, it inherits the default policies for an item, defined by the collection in which the item is archived. It's important to realize that these policies can altered for each item, bundle or bitstream, without altering other items or collection properties. Policies are really tied to items, bundles and bitstreams." source

So how would you do a mass-change of permissions? You can either write a curation task (DSpace 1.7 and newer) or a custom SQL query on the "resourcepolicy" table.

• DSpace 1.8: Curation System
• Curation Task Cookbook