Example systemd unit file for tomcat 7.x

tomcat.service

# Systemd unit file for tomcat
[Unit]
Description=Apache Tomcat Web Application Container
Wants=syslog.target network.target
After=syslog.target network.target

[Service]
Type=forking

Environment=JAVA_HOME=/usr/java/jre
Environment=CATALINA_PID=/run/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
Environment='CATALINA_OPTS=-Xms1G -Xmx1G -Djava.net.preferIPv4Stack=true'
Environment='JAVA_OPTS=-Djava.awt.headless=true'

ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/bin/kill -15 $MAINPID
PIDFile=/run/tomcat.pid
SuccessExitStatus=143

User=tomcat
Group=tomcat
UMask=0007
RestartSec=10
Restart=always

[Install]
WantedBy=multi-user.target