revamped Dockerfile to produce a smaller image (half the previous size)

Change-Id: Ia8d7cfc3ecbe167addc7bf7102a254900fbe8c2c

 FROM debian
 MAINTAINER Ali Al-Shabibi <ali@onlab.us>
 
-# Install required software
+# Add Java 8 repository
 ENV DEBIAN_FRONTEND noninteractive
 RUN echo debconf shared/accepted-oracle-license-v1-1 select true | debconf-set-selections && \
     echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee /etc/apt/sources.list.d/webupd8team-java.list && \
     echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee -a /etc/apt/sources.list.d/webupd8team-java.list && \
-    apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886 && \
-    apt-get update && \
-    apt-get install -y oracle-java8-installer oracle-java8-set-default maven git curl && \
-    apt-get clean && apt-get purge
+    apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
 
 # Set the environment variables
 ENV HOME /root
@@ -21,24 +18,28 @@ ENV KARAF_LOG /root/onos/apache-karaf-3.0.3/data/log/karaf.log
 ENV BUILD_NUMBER docker
 ENV PATH $PATH:$KARAF_ROOT/bin
 
-
-# Change to /src directory
+#Download and Build ONOS
 WORKDIR /src
-
-# Download ONOS
-RUN git clone https://github.com/opennetworkinglab/onos.git
-
-#Install ONOS
-WORKDIR /src/onos
-RUN     mkdir -p /root/Downloads && \
+RUN     apt-get update && apt-get install -y maven git curl oracle-java8-installer oracle-java8-set-default && \
+        git clone https://github.com/opennetworkinglab/onos.git && cd onos && \
+        mkdir -p /root/Downloads && \
         mvn clean install && \
-        ./tools/build/onos-package
+        tools/build/onos-package && \
+        rm -rf /root/.m2 && cd .. && \
+        rm -rf onos && \
+        apt-get remove --purge -y `apt-mark showauto` && \
+        apt-get install oracle-java8-set-default -y && \
+        apt-get clean && apt-get purge -y && apt-get autoremove -y && \
+        rm -rf /var/lib/apt/lists/* && \
+        rm -rf /var/cache/oracle-jdk8-installer && \
+        rm -rf /root/Downloads
 
 # Change to /root directory
 WORKDIR /root
 
+#Install ONOS
 RUN mkdir onos && \
-   cp /tmp/onos-*.docker.tar.gz . && \
+   mv /tmp/onos-*.docker.tar.gz . && \
    tar -xf onos-*.docker.tar.gz -C onos --strip-components=1 && \
    rm -rf onos-*.docker.tar.gz