While following the Android SDK installation guide, one is directed to optionally install a plugin, called Android Development Tools, for Eclipse IDE. If you installed Eclipse from Ubuntu’s repository like I did, the plugin installation will fail with an error, such as:
Cannot complete the install because one or more required items could not be found.
Software being installed: Android Development Tools 0.9.7.v201005071157-36220 (com.android.ide.eclipse.adt.feature.group 0.9.7.v201005071157-36220)
Missing requirement: Android Development Tools 0.9.7.v201005071157-36220 (com.android.ide.eclipse.adt.feature.group 0.9.7.v201005071157-36220) requires ‘org.eclipse.gef 0.0.0? but it could not be found
To fix this deficiency, add “http://download.eclipse.org/tools/gef/updates/releases/”, then install WST Server Adapters.