Schedule sessions cleanup

Set specific times for the Session Manager to scan for invalidated sessions. When used with persistent sessions, this feature has the following benefits:

• The scan for invalidated sessions can be scheduled for times of low application server activity, avoiding database contention between invalidation scans and read/write operations to service HTTP session requests.
• There may be significantly fewer database write operations when running with the End of servlet service write mode, because the session's last access time need not be written out after each HTTP session request. (Manual update and Time based write options already minimize the writing of the last access time.)

Usage considerations

• With scheduled sessions cleanup configured, HttpSession time-outs are not strictly enforced. Instead, all invalidation processing is handled at the configured invalidation times.
• HttpSessionBindingListener processing is handled at the configured invalidation times unless HttpSession.invalidate() is explicitly called.
• The HttpSession.invalidate() method immediately invalidates the session from both the session cache and the database.