Thanks for your reply.
The thing is that the report runs from the BOE takes long time, and sometimes error happens.
My Application structer is : Client URL -----> Web APP A servlet (which will generate a BOE token using SDK and new URL points to BOE server) ------> BOE Server RPT File -------> Web Service which is running on Web APP B ---------> return the report to client.
When I monitor the BOE server performance, I found the memory is used a lot(around 5G) and never release util I restart the BOE server.
I found when the Web APP A servlet logon to the server and create the token, but there is no way to logoff, because I think if logoff then the token can not be used by the user. but where should I do the logoff?