Install Oracle JDK on Ubuntu 12.04

UbuntuJDKInstall

Reference: [How do I install Oracle Java JDK 7?](http://askubuntu.com/questions/55848/how-do-i-install-oracle-java-jdk-7)

## 1. Install JDK

+ [Download](http://www.oracle.com/technetwork/java/javase/downloads/index.html) from Oracle page

+ Uncompress it

    tar -xvf jdk-7u2-linux-x64.tar.gz

+ Move the JDK 7 directory to /usr/lib

    sudo mkdir -p /usr/lib/jvm
    sudo mv ./jdk.1.7.0_02 /usr/lib/jvm/jdk1.7.0

## Config

+ Now run

    sudo update-alternatives --install "/usr/bin/java" "java" "/usr/lib/jvm/jdk1.7.0/bin/java" 1
    sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/lib/jvm/jdk1.7.0/bin/javac" 1
    sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/usr/lib/jvm/jdk1.7.0/bin/javaws" 1

+ Correct the file ownership and the permissions of the executables:

    sudo chmod a+x /usr/bin/java 
    sudo chmod a+x /usr/bin/javac 
    sudo chmod a+x /usr/bin/javaws
    sudo chown -R root:root /usr/lib/jvm/jdk1.7.0

 + Also you can use alternative command line to config

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

## Check

+ Run

    java -version

It should give output of java version "1.7.0".

## Web plugins

+ Enable mozilla firefox plugin:
    
    ln -s /usr/lib/jvm/jdk1.7.0/jre/lib/amd64/libnpjp2.so ~/.mozilla/plugins/

+  update the apparmor profile for firefox (or other browsers) in /etc/apparmor.d/abstractions/ubuntu-browsers.d/java

    # Replace the two lines:
    #  /usr/lib/jvm/java-*-sun-1.*/jre/bin/java{,_vm} cx -> browser_java,
    #  /usr/lib/jvm/java-*-sun-1.*/jre/lib/*/libnp*.so cx -> browser_java,
    # with those (or adapt to your new jdk folder name)
    /usr/lib/jvm/jdk*/jre/bin/java{,_vm} cx -> browser_java,
    /usr/lib/jvm/jdk*/jre/lib/*/libnp*.so cx -> browser_java,

+ Then restart apparmor:
    
    sudo /etc/init.d/apparmor restart

+ Verify

    [http://java.com/en/download/installed.jsp](http://java.com/en/download/installed.jsp)

## Chrome plugin (need to `mkdir` the plguins folder)

    ln -s /usr/lib/jvm/jdk1.7.0/jre/lib/amd64/libnpjp2.so /opt/google/chrome/plguins/
    
## Uninstall JDK

+ Remove the link

    sudo update-alternatives --remove "java" "/usr/lib/jvm/jdk[version]/bin/java"
    sudo update-alternatives --remove "javac" "/usr/lib/jvm/jdk[version]/bin/java"
    sudo update-alternatives --remove "javaws" "/usr/lib/jvm/jdk[version]/bin/javaws"
    
+ Remove file

    sudo mv /usr/lib/jvm/jdk[version]