code: public void activate() {
          if (entries.get() != null) {
              throw new IllegalStateException("Scope " + JoynrMessageScope.class.getSimpleName() + " is already active.");
          }
          logger.trace("Activating {} scope", JoynrMessageScope.class.getSimpleName());
          entries.set(new HashMap<Key<?>, Object>());
      }
docs: Call this method to activate the {@link JoynrMessageScope} for the current thread. It is not valid to call this
  method more than once.
  
  @throws IllegalStateException
  if you have already activated this scope for the current thread.