updated docker file

Dockerfile

@@ -1,4 +1,4 @@
-FROM java:8
+FROM openjdk:8-jre-slim
 
 MAINTAINER Timo Pagel <dependencycheckmaintainer@timo-pagel.de>
 
@@ -6,24 +6,28 @@ ENV user=dependencycheck
 ENV version_url=https://jeremylong.github.io/DependencyCheck/current.txt
 ENV download_url=https://dl.bintray.com/jeremy-long/owasp
 
-RUN wget -O /tmp/current.txt ${version_url} && \
- version=$(cat /tmp/current.txt) && \
- file="dependency-check-${version}-release.zip" && \
- wget "$download_url/$file" && \
- unzip ${file} && \
- rm ${file} && \
- mv dependency-check /usr/share/
-
-RUN useradd -ms /bin/bash ${user} && \
- chown -R ${user}:${user} /usr/share/dependency-check && \
- mkdir /report && \
- chown -R ${user}:${user} /report
+RUN apt-get update                                       && \
+    apt-get install -y wget                              && \
+    wget -O /tmp/current.txt ${version_url}              && \
+    version=$(cat /tmp/current.txt)                      && \
+    file="dependency-check-${version}-release.zip"       && \
+    wget "$download_url/$file"                           && \
+    unzip ${file}                                        && \
+    rm ${file}                                           && \
+    mv dependency-check /usr/share/                      && \
+    useradd -ms /bin/bash ${user}                        && \
+    chown -R ${user}:${user} /usr/share/dependency-check && \
+    mkdir /report                                        && \
+    chown -R ${user}:${user} /report                     && \
+    apt-get remove --purge -y wget                       && \
+    apt-get autoremove -y                                && \
+    rm -rf /var/lib/apt/lists/*
 
 USER ${user}
 
 VOLUME ["/src" "/usr/share/dependency-check/data" "/report"]
 
-WORKDIR /report
+WORKDIR /src
 
 CMD ["--help"]
 ENTRYPOINT ["/usr/share/dependency-check/bin/dependency-check.sh"]