add epicbox-java9 image

epicbox-java9/Dockerfile

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+FROM stepik/epicbox-base:stretch
+MAINTAINER Pavel Sviderski <[email protected]>
+
+ENV JAVA_INSTALLER_VERSION 9.0.1-1~webupd8~0
+
+# Add Oracle Java 9 (JDK9) repository
+RUN apt-get update && apt-get install -y --no-install-recommends gnupg1 \
+ && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886 \
+ && apt-get purge -y --auto-remove gnupg1 \
+ && rm -rf /var/lib/apt/lists/* \
+ && echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu xenial main" | tee /etc/apt/sources.list.d/webupd8team-java.list \
+ && echo oracle-java9-installer shared/accepted-oracle-license-v1-1 select true | debconf-set-selections
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    oracle-java9-installer=${JAVA_INSTALLER_VERSION} \
+ && rm -rf /var/lib/apt/lists/* /var/cache/oracle-jdk9-installer
+
+COPY java_lookup_main.sh /usr/local/bin/java_lookup_main.sh
+RUN chmod +x /usr/local/bin/java_lookup_main.sh

epicbox-java9/java_lookup_main.sh

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+#!/bin/bash
+# Grep *.class files in the given directory to find one with psvm method defined
+# Usage: java_lookup_main.sh DIRECTORY_PATH
+
+PSVM_REGEX="public static( final)? void main\(java\.lang\.String(\[\]|\.\.\.)\)"
+
+shopt -s nullglob
+for f in "$1"/*.class; do
+    if javap -p "$f" 2> /dev/null | grep -Pq "$PSVM_REGEX"; then
+        filename=$(basename "$f")
+        echo -n "${filename%.*}"
+        exit 0
+    fi
+done
+exit 1