how-to-install-oracle-java-on-ubuntu-14-04

Using a PPA

You can use WebUpd8 PPA (this will download the required files from Oracle and install JDK 8):

sudo apt-add-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java8-installer

Are PPA's safe to add to my system and what are some “red flags” to watch out for?

Also ensure your JAVA_HOME variable has been set to:

/usr/lib/jvm/java-8-oracle

For this you can use the following command (see step 3 of Manual Install to see how to make it permanent):

export JAVA_HOME=/usr/lib/jvm/java-8-oracle

Manual install

The tar.gz provided by Oracle don't have an actual installation process. You just extract those files to a location you want and add them to your path. So the process is the following:

• Download a .tar.gz from Oracle (here I will be using jdk-8u20-linux-x64.tar.gz);
• Extract it to somewhere;

• Move the extracted folder to /usr/lib/jvm. This is not required but it is the place where Java runtime software is installed, and where tools like IDE's may search for it:

  sudo mv /path/to/jdk1.8.0_20 /usr/lib/jvm/oracle_jdk8

• Before addin this jdk as an alternative, you can see that the new alternative is not listed:

  sudo update-alternatives --query java
  
  sudo update-alternatives --query javac

• Next, add the new jdk alternatives (2000 is the priority and feel free to pick a different number):

  sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/oracle_jdk8/jre/bin/java 2000
  
  sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/oracle_jdk8/bin/javac 2000

• Now you should see the new jdk listed and you can switch between the alternatives with this command:

  sudo update-alternatives --config java
  
  sudo update-alternatives --config javac

• Create a file /etc/profile.d/oraclejdk.sh with the following content (adapt the paths to reflect the path where you stored your JDK):

  export J2SDKDIR=/usr/lib/jvm/oracle_jdk8
  export J2REDIR=/usr/lib/jvm/oracle_jdk8/jre
  export PATH=$PATH:/usr/lib/jvm/oracle_jdk8/bin:/usr/lib/jvm/oracle_jdk8/db/bin:/usr/lib/jvm/oracle_jdk8/jre/bin
  export JAVA_HOME=/usr/lib/jvm/oracle_jdk8
  export DERBY_HOME=/usr/lib/jvm/oracle_jdk8/db

Done! Those paths will only be recognized after you logout or restart, so if you want to use them right away run source /etc/profile.d/oraclejdk.sh.