- Use Java:8 base image.

- Cleanup after running apt and installing Sahi for smaller layers.

Dockerfile

-FROM ubuntu:14.04
+FROM java:8
 MAINTAINER Nimrod Adar <nimrod@shore.co.il>
-RUN echo 'deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main' \
-> /etc/apt/sources.list.d/webupd8team-java-trusty.list && \
-apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886 && \
-echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select true \
-| sudo /usr/bin/debconf-set-selections
-RUN apt-get update && apt-get install -yf \
-oracle-java8-installer phantomjs libicu52 wget
-RUN cd /tmp && wget \
-http://garr.dl.sourceforge.net/project/sahi/sahi-v5/install_sahi_v50_20141105.jar
+RUN apt-get update && apt-get install -yf phantomjs libicu52 wget && \
+apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 COPY silent_install.xml /tmp/silent_install.xml
-RUN cd /tmp && java -jar install_sahi_v50_20141105.jar silent_install.xml
+RUN cd /tmp && wget \
+http://garr.dl.sourceforge.net/project/sahi/sahi-v5/install_sahi_v50_20141105.jar \
+&& java -jar install_sahi_v50_20141105.jar silent_install.xml && rm -rf /tmp/*
 COPY browser_types.xml /opt/sahi/userdata/config/browser_types.xml
 COPY phantomjs-sahi.js /opt/sahi/phantomjs-sahi.js
-RUN apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 EXPOSE 9999
 ENV _JAVA_OPTIONS -Djava.net.preferIPv4Stack=true
 ENV SAHI_HOME /opt/sahi