[LOG4J2-1950] Fix docker build with jdk9 requirements. Closes apache#84.

Dockerfile

@@ -13,18 +13,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM openjdk:7-alpine
+# FROM openjdk:7-alpine
+# Reverted to debian yet alpine does not include jdk9
+FROM openjdk:7-jdk
+
+# Require while jdk9 is unstable on debian
+RUN echo 'deb http://deb.debian.org/debian unstable main' >> /etc/apt/sources.list
 
 RUN set -ex \
     && mkdir /src \
-    && apk update \
-    && apk add curl \
-    && mkdir /opt \
+    && apt-get update \
+    && apt-get install -y \
+       curl \
+       openjdk-9-jdk-headless \
+    && ln -svT "/usr/lib/jvm/java-9-openjdk-$(dpkg --print-architecture)" /docker-java-9-home \
     && cd /opt \
-    && curl -fsSL http://www-us.apache.org/dist/maven/maven-3/3.3.9/binaries/apache-maven-3.3.9-bin.tar.gz -o maven.tar.gz \
+    && curl -fsSL http://www-us.apache.org/dist/maven/maven-3/3.5.0/binaries/apache-maven-3.5.0-bin.tar.gz -o maven.tar.gz \
     && tar -xzf maven.tar.gz \
     && rm -f maven.tar.gz
+
 COPY . /src
+
 RUN set -ex \
     && cd /src \
-    && /opt/apache-maven-3.3.9/bin/mvn verify
+    && /opt/apache-maven-3.5.0/bin/mvn verify --global-toolchains toolchains-docker.xml

src/changes/changes.xml

@@ -31,6 +31,9 @@
          - "remove" - Removed
     -->
     <release version="2.9.0" date="2017-MM-DD" description="GA Release 2.9.0">
+      <action issue="LOG4J2-1950" dev="ggregory" type="update" due-to="Pierrick HYMBERT">
+        Fix docker build with jdk9 requirements (#84).
+      </action>
       <action issue="LOG4J2-1801" dev="rpopma" type="update">
         Add more detail to WARN "Ignoring log event" messages printed to the console after log4j was shut down.
       </action>

toolchains-docker.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF8"?>
+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one or more
+  ~ contributor license agreements. See the NOTICE file distributed with
+  ~ this work for additional information regarding copyright ownership.
+  ~ The ASF licenses this file to You under the Apache license, Version 2.0
+  ~ (the "License"); you may not use this file except in compliance with
+  ~ the License. You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the license for the specific language governing permissions and
+  ~ limitations under the license.
+  -->
+<toolchains>
+  <!-- JDK toolchains -->
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.7</version>
+      <vendor>sun</vendor>
+    </provides>
+    <configuration>
+      <jdkHome>/docker-java-home</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>9</version>
+      <vendor>sun</vendor>
+    </provides>
+    <configuration>
+      <jdkHome>/docker-java-9-home</jdkHome>
+    </configuration>
+  </toolchain>
+
+  <!-- other toolchains -->
+</toolchains>