This seems to be a bug in the latest release of the ADT package (as of March 13, 2014). Updating through the Eclipse Install New Software window should fix this. To do this, you can try the following:
- In Eclipse, go to Help → Install new software;
- Select the main update site that has the URL
http://dl-ssl.google.com/android/eclipse ; - At the bottom, turn off “Contact all update sites during installation to find the necessary software” ; this causes problems during the upgrade;
- Check developer tools;
- Perform the rest of the update;
source share