Docker – Quick Java 8 or Java 7 Dev Environment with Dockers

This article represents code samples which could be used to build and start Java 7 or Java 8 Docker containers appropriately based on the 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 to mention one or more important points. Also, sorry for the typos.

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 dockerfile 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 Java8 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 name as “java7” and, “./startJava.sh -v 8 java8” to start the Java 8 Container with 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"#!/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
  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