Run Tomcat 6/7 As tomcat Or Any Other User

                                      The default user and group are configured in /etc/default/tomcat.The file is format is show below

# Run Tomcat as this user ID. Not setting this or leaving it blank will use the

# default of tomcat7.

TOMCAT7_USER=tomcat7

# Run Tomcat as this group ID. Not setting this or leaving it blank will use

# the default of tomcat7.

TOMCAT7_GROUP=tomcat7

For Changing User Default User And Group In Tomcat:-

1. Stop the tomcat service
2. Editing the file /etc/default/tomcat7.Change the user and group in thi file

              (Add new user name instead of tomcat7)

3. Change ownership of the folder /var/log/tomcat7 and /var/lib/tomcat7/webapps

            and all of it's files.

sudo chown -R newuser:newgroup /var/log/tomcat7

sudo chown -R newuser:newgroup /var/lib/tomcat7/webapps

sudo chown -R newuser:newgroup /var/log/tomcat7

     4. Optional :- Change ownership of the working folder

sudo chown newuser:newgroup /var/cache/tomcat7

sudo chown -R newuser:newgroup /var/cache/tomcat7/Catalina

     5. Make config files readable. Here you have two options:

Either add you new user to the tomcat7 group by:

sudo usermod -a -G tomcat7 newuser

          OR  change ownership of the config files:

sudo chown -R :newgroup /var/lib/tomcat7/conf/*

     6. Restarted the Server and Started the tomcat service