Fcron virtual Memory problem

[Thomas Papke <tp thopap de>]

i have an problem with an limit of virtual memory. I have an java 
program that runs normal started as user quiet good - it need about 1 
minute to query a lot of data from the database and need about 500meg of 
virtual memory. The problem is: If i configure that program as daily job 
in fcrontab of that user - the execution of the programm need more than 
6times longer and "top" said that the program only take 170meg of 
virtual memory. In my /etc/security/limits.conf is nothing defined and 
the programm is started without nice or something like that???

Where could be the problem that the program is directly invoked faster 
than invoked by fcron?