From my linux server, I deployed one web application on tomcat server. And I configured log4j to write log and rotate every hour. But when it create new log every times, it use "640" file permission by default.
rw-r----- 1 myuser myuser 664 Jun 6 11:00 mylog.log
File permissions are determined by the
umask - there's no way to change it in log4j itself.