@Override
    public void event(BundleEvent event, Collection<BundleContext> contexts) {
        if (event.getType() != BundleEvent.UNINSTALLED) return;

        synchronized (this) {
            allowedDuplicates.remove(event.getBundle());
        }
    }
Cleans up the allowed duplicates when a bundle is uninstalled.
jdisc_core/src/main/java/com/yahoo/jdisc/core/BundleCollisionHook.java