Hello,
along with the removal of unsupported cluster code in Community with Alfresco 4.2, the ehcache-default.xml is no longer present in the Community version of Alfresco as well. The caches for the Community version are configured in the cache-context.xml that can be found in /<tomcat>/webapps/alfresco/WEB-INF/classes/alfresco/. Unfortunately, the default simple cache does not seem to support persistent cache entries. Unless Alfresco or someone from the Community decides to add a cache implementation capable of persisting cache entries, you no longer have the option of keeping URL tickets between restarts.
Regards
Axel