add java:openjdk-8-jre-alpine

.travis.yml

@@ -4,6 +4,8 @@ services: docker
 env:
   - VERSION=openjdk-9-jre
   - VERSION=openjdk-9-jdk
+  - VERSION=openjdk-8-jre VARIANT=alpine
+  - VERSION=openjdk-8-jdk VARIANT=alpine
   - VERSION=openjdk-8-jre
   - VERSION=openjdk-8-jdk
   - VERSION=openjdk-7-jre
@@ -16,8 +18,8 @@ install:
 
 before_script:
   - env | sort
-  - cd "$VERSION"
-  - image="java:$VERSION"
+  - cd "${VERSION}${VARIANT:+/$VARIANT}"
+  - image="java:${VERSION}${VARIANT:+-$VARIANT}"
 
 script:
   - docker build -t "$image" .

openjdk-8-jdk/alpine/Dockerfile

@@ -0,0 +1,29 @@
+FROM alpine:3.3
+
+# A few problems with compiling Java from source:
+#  1. Oracle.  Licensing prevents us from redistributing the official JDK.
+#  2. Compiling OpenJDK also requires the JDK to be installed, and it gets
+#       really hairy.
+
+# Default to UTF-8 file.encoding
+ENV LANG C.UTF-8
+
+# add a simple script that can auto-detect the appropriate JAVA_HOME value
+# based on whether the JDK or only the JRE is installed
+RUN { \
+		echo '#!/bin/sh -e'; \
+		echo; \
+		echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; \
+	} > /usr/local/bin/docker-java-home \
+	&& chmod +x /usr/local/bin/docker-java-home
+
+ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
+
+ENV JAVA_VERSION 8u72
+ENV PATH $PATH:/usr/lib/jvm/java-1.8-openjdk/bin
+
+RUN set -x \
+	&& apk add --no-cache \
+		"openjdk8>=${JAVA_VERSION/u/.}" \
+		ca-certificates \
+	&& [ "$JAVA_HOME" = "$(docker-java-home)" ]

openjdk-8-jre/alpine/Dockerfile

@@ -0,0 +1,28 @@
+FROM alpine:3.3
+
+# A few problems with compiling Java from source:
+#  1. Oracle.  Licensing prevents us from redistributing the official JDK.
+#  2. Compiling OpenJDK also requires the JDK to be installed, and it gets
+#       really hairy.
+
+# Default to UTF-8 file.encoding
+ENV LANG C.UTF-8
+
+# add a simple script that can auto-detect the appropriate JAVA_HOME value
+# based on whether the JDK or only the JRE is installed
+RUN { \
+		echo '#!/bin/sh -e'; \
+		echo; \
+		echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; \
+	} > /usr/local/bin/docker-java-home \
+	&& chmod +x /usr/local/bin/docker-java-home
+
+ENV JAVA_VERSION 8u72
+ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk/jre
+
+RUN set -x \
+	&& apk add --no-cache \
+		"openjdk8>=${JAVA_VERSION/u/.}" \
+		ca-certificates \
+	&& [ "$JAVA_HOME" = "$(docker-java-home)" ]
+