Which User Is Running Tomcat?

Run following command to find out the tomcat process

ps auxwww | grep -v grep | grep tomcat 

From there you will find out the tomcat process and from there you can see which user is starting this.

For eg see the following output

vidyadhar@ubuntu:~$ ps auxwww | grep -v grep | grep tomcat
root      1941  0.2  1.7 419224 35208 ?        Sl   Aug12   0:06 /usr/lib/jvm/java-6-sun/bin/java -Djava.util.logging.config.file=/usr/local/tomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/usr/local/tomcat/endorsed -classpath /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar -Dcatalina.base=/usr/local/tomcat -Dcatalina.home=/usr/local/tomcat -Djava.io.tmpdir=/usr/local/tomcat/temp org.apache.catalina.startup.Bootstrap start

In above eg 1941 is a tomcat process which is started by root user.

If you want to see all the user run below command

more /etc/passwd