Install Official Eclipse on Ubuntu

If you've downloaded Eclipse from their official website, follow these steps for the installation. (Ubuntu 12.04 LTS)

Extract the eclipse.XX.YY.tar.gz using
```
tar -zxvf eclipse.XX.YY.tar.gz
```
Copy the extracted folder to /opt
```
sudo cp -r eclipse.XX.YY /opt
```

Create a desktop file and install it:

gedit eclipse.desktop

and copy the following to the eclipse.desktop file.

[Desktop Entry]
Name=Eclipse 
Type=Application
Exec=eclipse
Terminal=false
Icon=eclipse
Comment=Integrated Development Environment
NoDisplay=false
Categories=Development;IDE;
Name[en]=Eclipse

then execute the following command to automatically install it in the unity:

sudo desktop-file-install eclipse.desktop

Create a symlink in /usr/local/bin using

cd /usr/local/bin
sudo ln -s /opt/eclipse/eclipse

For eclipse icon to be displayed in dash, eclipse icon can be added as
```
sudo cp /opt/eclipse/icon.xpm /usr/share/pixmaps/eclipse.xpm
```

　　That's it.