Long response time of JasperReports Server on Tomcat after a period of no activity

Issue Description

After not using JasperReports Server for a couple of hours, I tried to access the JasperReports Server login page, and it took over a minute to finish loading. After this, JasperReports Server has normal response times until another long period of inactivity.

The error in the logs was:

java.util.prefs.FileSystemPreferences syncWorld WARNING: Couldn't flush user prefs:
java.util.prefs.BackingStoreException: Couldn't get file lock.
java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode WARNING: Could not lock User prefs. Unix error code 2.

Resolution

This appears to be due to the Java process not being able to write to the user root directory. The solution is to add the folder /.java/.userPrefs/ in the tomcat directory and define tomcat7 as the owner for all objects in the tomcat directory.

Ref. Case 00059447