code: @Nonnull
    public static final String getSingletonScopeKey (@Nonnull final Class <? extends AbstractSingleton> aClass)
    {
      ValueEnforcer.notNull (aClass, "Class");
  
      // Preallocate some bytes
      return new StringBuilder (DEFAULT_KEY_LENGTH).append ("singleton.").append (aClass.getName ()).toString ();
    }
docs: Create the key which is used to reference the object within the scope.
  
  @param aClass
  The class for which the key is to be created. May not be
  <code>null</code>.
  @return The non-<code>null</code> key.