This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
In Eclipse's menu toolbar, click on "Project" then click on "Properties". Your project properties window should appear. On the left-hand side tree, click on "Java Build Path". There will be 4 tabs on the right-hand side window. Click on "Libraries". In my configuration, java.lang.Object is in the rt.jar provided by the JRE. Make sure you have a jar that has java.lang.Object in your libraries tab and that the jar exists (just in case you upgraded your JRE or something like that).