Java on Ubuntu

Install sun-java

java -version

sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner"

sudo apt-get update

sudo apt-get install sun-java6-jre sun-java6-plugin

java -version

sudo update-alternatives --config java

java -version

killall firefox-bin

ifconfig

sudo apt-get remove icedtea6-plugin openjdk-6-jre

sudo apt-get install sun-java6-plugin

sudo apt-get install sun-java6-plugin auto-remove

sudo update-alternatives --install /usr/lib/mozilla/plugins/mozilla-javaplugin.so mozilla-javaplugin.so /usr/lib/jvm/java-6-sun/jre/lib/i386/libnpjp2.so 1

java -version

ifconfig

Install Oracle Java (2014 - for webex etc)

sudo add-apt-repository ppa:webupd8team/java

After that, update package lists via:

sudo apt-get update

To install Oracle Java 8, run:

sudo apt-get install oracle-java8-installer

Change the number 8 to 6 (or 7) in the code to install Java 6 (or 7).

While installation, you’ll be asked to agree the license and then the installer start downloading Java file from oracle website and install it on your system.

To set the default Java, run:

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

Also change number 8 to the Java version you want.