Created attachment 1169239 [details]
small test app to reproduce behavior

Description of problem:
The systemd unit terminates the tomcat process prematurely, therefore not allowing it to shutdown gracefully. The direct effect of this is that sessions in the session manager are not persisted to disk and restored after a restart, resulting in a loss of session data (unless you are replicating data within a cluster).

Version-Release number of selected component (if applicable):
tomcat-7.0.54-1.el7.noarch

How reproducible:
Always

Steps to Reproduce:
1. yum install tomcat
2. cp reproducer.war /usr/share/tomcat/webapps/
3. service tomcat start
4. curl http://localhost:8080/reproducer/getSession.jsp
5. service tomcat stop
6. ls /usr/share/tomcat/work/Catalina/localhost/reproducer/SESSIONS.ser

Actual results:
The session created by the curl request is not persisted into SESSIONS.ser.

Expected results:
The session created by the curl request is persisted to SESSIONS.ser

Additional info:
When the process successfully completes (with FINE logging on the StandardManager (org.apache.catalina.session.StandardManager.level = FINE)), you see the following along with other shutdown messages:

~~~
Jun 17, 2016 4:45:08 PM org.apache.catalina.session.StandardManager doUnload
FINE: Unloading persisted sessions
Jun 17, 2016 4:45:08 PM org.apache.catalina.session.StandardManager doUnload
FINE: Saving persisted sessions to SESSIONS.ser
Jun 17, 2016 4:45:08 PM org.apache.catalina.session.StandardManager doUnload
FINE: Unloading 4 sessions
Jun 17, 2016 4:45:08 PM org.apache.catalina.session.StandardManager doUnload
FINE: Expiring 4 persisted sessions
Jun 17, 2016 4:45:08 PM org.apache.catalina.session.StandardManager doUnload
FINE: Unloading complete
~~~

When you call the service stop, it terminates before the shutdown can complete (almost immediately after calling stop):

~~~
INFO: Server startup in 3501 ms
Jun 17, 2016 4:58:20 PM org.apache.catalina.core.StandardServer await
INFO: A valid shutdown command was received via the shutdown port. Stopping the Server instance.
Jun 17, 2016 4:58:20 PM org.apache.coyote.AbstractProtocol pause
INFO: Pausing ProtocolHandler ["http-bio-8080"]
~~~