$ sudo -u gerrit2 jcmd 2347 GC.class_histogram|grep -i jetty
 num     #instances         #bytes  class name
----------------------------------------------
   5:      10042773     1205132760  org.eclipse.jetty.server.session.SessionData
   8:      10042773      883764024  org.eclipse.jetty.server.session.Session
  11:      10042773      482053104  org.eclipse.jetty.server.session.Session$SessionInactivityTimer$1
  13:      10042779      321368928  org.eclipse.jetty.util.thread.Locker
  14:      10042773      321368736  org.eclipse.jetty.server.session.Session$SessionInactivityTimer
  17:      10042779      241026696  org.eclipse.jetty.util.thread.Locker$Lock