Friday 18 April 2014

Install Oracle Java 7 in Ubuntu or Linux Mint via PPA

This package provides Oracle Java JDK 7 (which includes Java JDK, JRE and the Java browser plugin). However, you can't only install Oracle JRE - the PPA only provides the full Oracle JDK7 package.

To add PPA and install the latest Oracle Java 7 in Ubuntu (supports Ubuntu 13.10, 13.04, 12.10, 12.04 and 10.04) or Linux Mint, use the commands below:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java7-installer

After the installation finishes, if you wish to see if it was successful, you can run the following command:
java -version
 
It should return something like this:
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

The package installs all the Java binaries, so you can also try "javac -version" which should return "javac 1.7.0_51" and so on (the "_51" part of the version can be different because they are constantly updating the PPA with the latest Oracle Java 7 version). The current JDK version in the PPA is Oracle Java 7 Update 51 (7u51).

If for some reason, the Java version in use is not 1.7.0, you can try to run the following command: 
sudo update-java-alternatives -s java-7-oracle

Update: the installer now requires you accept the Oracle license before the installation begins. This is only required once. If for some reason you need the installation to be automated, you can run the following command to automatically accept the Oracle license:
echo oracle-java7-installer shared/accepted-oracle-license-v1-1 select true | sudo /usr/bin/debconf-set-selections 
 
Setting Java environment variables

To automatically set up the Java 7 environment variables, you can install the following package:
sudo apt-get install oracle-java7-set-default

If you've already installed oracle-java6-set-default or oracle-java8-set-default, they will be automatically removed when installing oracle-java7-set-default (and the environment variables will be set for Oracle Java 7 instead). 

Removing Oracle Java 7

If you don't want to use Oracle Java (JDK) 7 anymore on your Ubuntu / Linux Mint computer and want to go back to OpenJDK, all you have to do is remove the Oracle JDK7 Installer and the previous Java (OpenJDK, etc.) version will be used:
sudo apt-get remove oracle-java7-installer
 
Source: http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html 

how to repair grub and get ubuntu back after installing windows

First make sure that you have turned off fast boot from Windows power settings and disabled secure boot  from BIOS.

Boot from Ubuntu CD, open the terminal and run the following commands

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install boot-repair
 
After completing the installation you can launch it from System-> Administration-> Boot-Repair menu if you use Gnome, or search "boot-repair" in the dash if you use Unity.


Select the recommended Boot repair options as shown in the screenshot and follow the steps suggested by Boot Repair



Initial screen


Source: http://askubuntu.com/questions/88384/how-can-i-repair-grub-how-to-get-ubuntu-back-after-installing-windows


EDIT: Recently I upgraded from ubuntu 12.04 to  14.04. I faced similar problem and this solution worked like a charm !