Solution : https://service.sap.com/sap/support/notes/696782 (SAP Service marketplace login required)
Key words :
symptom user sessions, sap j2ee engine 6, invalid session reason, invalid session error, invalid sessionwhere [methodname], http session, [methodname] called, problems logging, logs similar, service pack 18
Related Notes :
| 700864 | Upgrade to SP19 from lower versions. |
| 691272 | SAP J2EE Engine 6.20: List of fixes done in PL19 |
| 529088 | Patches for the SAP J2EE engine |