JDK setup

“Java” is one of the most popular and common language in this world.

It's everywhere, and you need some library to execute these programs.

Get Java

2 versions of Java are available:

• JRE as Java Runtime Environment. For end-users
• JDK as Java Devolpment Kit. For developers and application servers

Download JRE: https://java.com/getjava‎

Download JDK: http://www.oracle.com/technetwork/java/javase/downloads/index.html

Linux installation

On a server, I advised you to put the JDK (Developer Kit) instead of the JRE (Run-time only). The JDK include the JRE   I also advised you to use the official ORACLE library, instead of the OpenSource (OpenJDK). Automatic install (Ubuntu) On Ubuntu based distributions you can do the following:

1. add-apt-repository ppa:webupd8team/java
2. apt-get update
3. apt-get install oracle-java7-installer oracle-jdk7-installer

To remove the repository:

1. apt-add-repository --remove ppa:webup8team/java

Guillaume Diaz Page 5 / 30 version 1.8Continuous Integration Platform # Linux Manual install (debian) You've to retrieve the JDK / JRE from the sun website http://www.oracle.com/technetwork/java/javase/downloads/index.html Download Oracle JDK Download link: http://download.oracle.com/otn-pub/java/jdk/7u9-b05/jdk-7u9-linux- x64.tar.gz

1. wget -c --no-cookies --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F"

"<DOWNLOAD_URL>" --output-document="<TARGET_FILE_NAME>" Installation

1. tar -xzvf jdk-7u9-linux-x64.tar.gz
2. mv jdk1.7.* /usr/lib/jvm
3. cd /usr/lib/jvm

Adjust symlink

1. rm /usr/lib/jvm/default-java
2. ln -s /usr/lib/jvm/jdk1.7.0_17/ /usr/lib/jvm/default-java

Perform update

1. update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.7.0_09/bin/java 1065
2. update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.7.0_09/bin/javac 1065
3. update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk1.7.0_09/bin/jar 1065
4. update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.7.0_09/bin/javaws 1065

Choose system version

1. update-alternatives --config java

Check result

1. java -version

Update environment You need to add an environment variable:

1. vim /etc/profile

Ubuntu:

1. vim /etc/environment

export JAVA_HOME="/usr/lib/jvm/jdk1.7.0_09" if [ "`id -u`" -eq 0 ]; then PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:$JAVA_HOME/bin" else PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:$JAVA_HOME/bin" fi export PATH Guillaume Diaz Page 6 / 30 version 1.8Continuous Integration Platform # Linux Reminders Don't forget to adjust the JAVA related services:  Tomcat /etc/default/tomcat7  Eclipse IDE eclipse.ini  Jenkins  etc. Java # OpenJdk It’s always good to setup OpenJDK as well, especially for the old version as there is more updates.

1. apt-get install openjdk-6-jdk