This article represents code samples which could be used to build and start Java 7 or Java 8 Docker containers appropriately based on needs with a single script and command such as “./startJava.sh -v 7 Java7” for Java 7 and “./startJava.sh -v 8 java8” for Java 8. This would be useful to try and test your Java code against Java 7 and Java 8 versions very easily based on the fact that you could start both Java7 and Java8 containers simultaneously and, run your code in these containers at the same time for testing. Please feel free to comment/suggest if I missed mentioning one or more important points.
Following are the key points described later in this article:
- Java 7 Dev Environment Dockerfile
- Java 8 Dev Environment Dockerfile
- Single Shell Script to Start Java 7 or Java 8 Development Environment
Java 7 Dev Environment Dockerfile
Following is docker file to build Java 7 image. Save the file as java7.df for the code example (shell script startJava.sh) to work.
FROM centos:centos6 RUN mkdir /opt/jdk RUN cd /opt RUN yum -y install wget tar RUN wget --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/7u79-b15/jdk-7u79-linux-x64.tar.gz RUN tar -zxf jdk-7u79-linux-x64.tar.gz -C /opt/jdk RUN update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.7.0_79/bin/java 100 RUN update-alternatives --install /usr/bin/javac javac /opt/jdk/jdk1.7.0_79/bin/javac 100
Java 8 Dev Environment Dockerfile
Following is Dockerfile to build Java 8 image. Save the file as java8.df for the code example (shell script startJava.sh) to work.
FROM centos:centos6 RUN mkdir /opt/jdk RUN cd /opt RUN yum -y install wget tar RUN wget --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u5-b13/jdk-8u5-linux-x64.tar.gz RUN tar -zxf jdk-8u5-linux-x64.tar.gz -C /opt/jdk RUN update-alternatives --install /usr/bin/java java /opt/jdk/jdk1.8.0_05/bin/java 100 RUN update-alternatives --install /usr/bin/javac javac /opt/jdk/jdk1.8.0_05/bin/javac 100
Single Shell Script to Start Java 7 or Java 8 Dev Environment
Save the following script as startJava.sh. Save the above two Dockerfiles as java7.df and java8.df in the same folder as the script below. Execute the command such as “./startJava.sh -v 7 java7” to start a Java 7 container with the name as “java7” and, “./startJava.sh -v 8 java8” to start the Java 8 Container with the name as “java8”. You could then access your source code on your m/c as the volume is mounted appropriately in the script below (/c/Users:/mnt/Users).
#!/bin/sh if [ $# == 0 ]; then echo "This script expecs version and container name as argument. Example: ./startJava.sh -v 7 java" exit 100 fi if [ $1 == '-v' ]; then expr $2 + 1 2> /dev/null if [ $? = 0 ]; then echo "Version: $2" else echo "Version can only be numeric. Value supported are 7, 8" exit 100 fi else echo "This script expecs version and container name as argument. Example: ./startJava.sh -v 7 java" exit 100 fi docker stop $3;docker rm $3 java_image="" java_df="" if [ $2 == 8 ]; then java_image="java8_base" java_df="java8.df" else if [ $2 == 7 ]; then java_image="java7_base" java_df="java7.df" else echo "This script only supports Java containers for version 7 or 8. Please try again!" exit 100 fi fi # Build Java image if it does not exists # if [ `docker images $java_image | wc -l` -lt 2 ]; then echo "Docker Image $java_image do not exist..." echo "Builing docker image $java_image" if [ -f $java_df ]; then docker build -t $java_image -f $java_df . else echo "Can't find Dockerfile $java_df in the current location" exit 200 fi fi docker run --privileged=true -ti -dP --name $3 -v /c/Users:/mnt/Users $java_image /bin/bash docker exec -ti $3 /bin/bash