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Table of Contents

Introduction

Manual installation of Oracle Java (which is preferred to Open Java, which often doesn't work right) is a bit tedious: one needs to find and download the latest release and manually set up all the path variables. The PPA from webupd8 developer team simplifies our task and provides us with an installer which does all this for us and enables auto-updates.

Installation

First, add the PPA:

add-apt-repository ppa:webupd8team/java

Then update the software information:

apt-get update

Then install Java (replace 8 with another Java version you might want instead, like 6 or 7):

apt-get install oracle-java8-installer

The installer takes a while since it needs to download the latest Java installer from the Oracle site.

Setting Java environment variables

To automatically set up the Java 8 environment variables, you can install the following package:

sudo apt-get install oracle-java8-set-default

Below /etc/profile.d there are two files jdk.csh and jdk.sh who contain the environment variables definitions, here is the content of jdk.sh :

export J2SDKDIR=/usr/lib/jvm/java-8-oracle
export J2REDIR=/usr/lib/jvm/java-8-oracle/jre
export PATH=$PATH:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
export JAVA_HOME=/usr/lib/jvm/java-8-oracle
export DERBY_HOME=/usr/lib/jvm/java-8-oracle/db

Verification

Make sure something silly didn't happen and your alternatives were set to Oracle Java:

java -version

Expected output (with Oracle Java 8):

java version "1.8.0_40"
Java(TM) SE Runtime Environment (build 1.8.0_40-b25)
Java HotSpot(TM) Server VM (build 25.40-b25, mixed mode)

Wrong output (with OpenJRE)

OpenJDK Runtime Environment (IcedTea6 1.13.6) (6b34-1.13.6-1ubuntu0.12.04.1)
OpenJDK Server VM (build 23.25-b01, mixed mode)

Then

javac -version

Expected output (with Oracle Java 8):

javac 1.8.0_40

(Without Oracle Java, OpenJDK is rarely installed)

If the wrong Java is chosen, run:

update-alternatives --config java
update-alternatives --config javac
update-alternatives --config javaws

and choose Oracle's needed version.

Then run

update-initramfs -u

Troubleshooting

Firewall/cacher

The installer fetches the latest Java binary via wget. Most of the time, the download fails because either the firewall blocks it or because the cacher doesn't allow it. Since Java updates are not very frequent, we can turn off the firewall while installing, but the cacher can at least be configured for a permanent bypass. Create /etc/apt/apt.conf.d/03java-bypass with the following contents:

/etc/apt/apt.conf.d/03java-bypass
Acquire::http::Proxy {
    download.oracle.com DIRECT;
};

This will ensure that downloads from download.oracle.com initiated by pre/post-install scripts do not go through the cacher. The ideal solution would be to make them cached but that needs a regex hack for apt-cacher-ng (to stop it from rejecting this site as a cacheable source) which I was not able to develop yet.

Architecture

If your host architecture differs from LTSP chroot, you won't be able to install Java this way. Chrooting will make the chroot report the host's architecture to the installer, which causes it to download the wrong binary. Generally, chroots should be kept the same architecture as host, but if they must be different, one can still install Java this way if live-boot from the correct architecture media is done and chroot is entered from it.

Browser plugin

In some cases, the presence of IcedTea Java Browser plugin (OpenJRE implementation) will prevent Oracle Java plugin from working or even being installed. It is advised to remove all icedtea packages either prior to Oracle Java installation or after it. In the latter case, reinstallation of Oracle Java might be required to install the plugin properly.

Note: Oracle Java will not work in Google Chrome (since Google changed the plugin implementation system from previous standard) until Oracle issues an updated plugin.

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