>In the following example, the scope annotation <code>@Singleton</code> ensures
 that we only have one Log instance:

 <pre>
   &#064;Singleton
   class Log {
     void log(String message) { ... }
   }</pre>
 
 <p>The injector generates an error if it encounters more than one scope
 annotation on the same class or a scope annotation it doesn't support.

 <p>A scope annotation:
 <ul>
   <li>is annotated with <code>@Scope</code>, <code>@Retention(RUNTIME)</code>,
      and typically <code>@Documented</code>.<