Dockerfile available on Github: https://github.com/drosenbauer/raspberrypi3-docker/blob/master/tomcat8/Dockerfile

Tomcat is installed to /usr/local/tomcat, with the webapps directory at /usr/local/tomcat/webapps/. Java is installed, per the rpi3-jdk8 image, to /usr/lib/jvm/jdk-8-oracle-arm32-vfp-hflt. A $JAVA_HOME environment variable is defined in the image with that location specified.

Port 8080 is exposed.