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. Download JRE: https://java.com/getjava‎
• JDK as Java Devolpment Kit. For developers and application servers. The JDK includes the corresponding JRE. Download JDK: http://www.oracle.com/technetwork/java/javase/downloads/index.html

You need to install the JDK on your development station & servers.

Linux installation

On a server, I advise you to put the JDK instead of the JRE. Many services requires the JDK such as JMX.

While on Windows ORACLE java is almost the only JVM available, on Linux you can choose your JVM vendor: OpenJDK, ORACLE, .... I advise you to use the official ORACLE library, instead of the OpenSource OpenJDK due to stability issues and JavaFX2 compability.

ORACLE JVM automatic installation (ubuntu)

This is for Ubuntu based distributions only.

Add a new repository:

add-apt-repository ppa:webupd8team/java
apt-get update

Install ORACLE JDK packages:

apt-get install oracle-java7-installer oracle-jdk7-installer

This will download the latest JDK, install it automatically and set the new JVM as the default one.

To remove the repository:

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

ORACLE JVM manual installation (debian)

You've to retrieve the JDK / JRE from the sun website

• Through a graphical interface: http://www.oracle.com/technetwork/java/javase/downloads/index.html
• Using wget:

export ORACLE_JVM_URL='http://download.oracle.com/otn-pub/java/jdk/'''7u45-b18'''/jdk-7u45-linux-x64.tar.gz'
export ORACLE_JVM_FILENAME='jdk-linux-x64.tar.gz'
wget -c --no-cookies --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F" \
$ORACLE_JVM_URL --output-document=$ORACLE_JVM_FILENAME

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