code: @Override
      public T addClass(Class<?> clazz) throws IllegalArgumentException {
          Validate.notNull(clazz, "Clazz must be specified");
  
          return addClasses(clazz);
      }
docs: /*
  (non-Javadoc)
  
  @see org.jboss.declarchive.api.container.ClassContainer#addClass(java.lang.Class)