Before we can start coding in Joomla!, we need to be able to work with the Subversion (SVN) source code repository. Subversion is a third-party plugin for Eclipse, so we need to use the Eclipse Update Manager to install it. To do this, navigate to Help / Software Updates, as shown below.
The Software Updates and Add-ons dialog will display. Select the "Available Software" tab. The list of available update sites will display. Press the "Add Site" button to display the Add Site dialog. Enter "http://subclipse.tigris.org/update_1.8.x" as the URL, as shown below. NOTE: 1.8 is the current version as of the date of this update: July 20, 2012
Press OK and the "Available Software" tab should again display, this time with additional options from the Subclipse site. Select all Subclipse options as shown below. Then press the "Install" button.
Eclipse will work for a minute and then display the Install window, shown below. Press the "Next" button. A "Review Licenses" window appears. Click "I accept the terms of the license agreements". Now click finish.
After the files have been downloaded and installed, Eclipse will show the message below recommending that you restart Eclipse. Press "Yes" and Eclipse will restart.
Once Eclipse has restarted, we can test that the Subversion plugin is working. Select File / Import as shown below.
Then expand the SVN element in the tree. You should see an option called "Checkout Projects from SVN", as shown below.
At this point, the plugin has been installed successfully. Press "Cancel" to cancel the import. (We'll import the Joomla! project in the next section.)