Intalling Java 7 on Ubuntu Natty (11.04)

To install Java 7 on Ubuntu

To install the JRE

$ sudo add-apt-repository ppa:dlecan/openjdk
$ sudo apt-get update
$ sudo apt-get install openjdk-7-jre

To install the JDK



$ sudo add-apt-repository ppa:dlecan/openjdk
$ sudo apt-get update
$ sudo apt-get install openjdk-7-jdk.

How to set JAVA_HOME environment variable in Ubuntu

One way that you can set your JAVA_HOME variable and add to your PATH, is be doing the folowing. 

As 'sudo' open up /etc/bash.bashrc and add the following to the end of the file. 

NOTE: Set the java path to whatever the actual path is on your environment if it does not match /usr/lib/jvm/java

JAVA_HOME=/usr/lib/jvm/java
export JAVA_HOME
PATH=$PATH:$JAVA_HOME/bin
export PATH

When you reboot, try running the following:

$ echo $JAVA_HOME
/usr/lib/jvm/java
 echo $PATH
[probably lots of paths]:/usr/lib/jvm/java/bin

Credits : http://www.zimbio.com/the+ubuntu+guy/articles/82/How+set+JAVA_HOME+environment+variable+Ubuntu 

Install an RPM Package on Ubuntu Linux

Installing software on Ubuntu usually entails using Synaptic or by using an apt-get command from the terminal. Unfortunately, there are still a number of packages out there that are only distributed in RPM format.

There’s a utility called Alien that converts packages from one format to the other. This doesn’t always mean that an rpm will work on your system, though. You will need to install some prerequisite software packages in order to install alien, however. These packages include gcc and make.

Run this command to install alien and other necessary packages:

sudo apt-get install alien dpkg-dev debhelper build-essential

To convert a package from rpm to debian format, use this command syntax. The sudo may not be necessary, but we’ll include it just in case.

sudo alien packagename.rpm

To install the package, you’ll use the dpkg utility, which is the internal package management tool behind debian and Ubuntu.

sudo dpkg -i packagename.deb

The package should now be installed, providing it’s compatible with your system.

Source : http://www.howtogeek.com/howto/ubuntu/install-an-rpm-package-on-ubuntu-linux/