Trivial Description
Class IndexTracker is a package protected class that must be passed as an argument to LuceneIndexMBeanImpl. For OSGi environments the MBean LuceneIndexMBeanImpl is registered by LuceneIndexProviderService that is located in the same package like IndexTracker. For nin OSGi environments LuceneIndexMBeanImpl cannot be used, since class IndexTracker is not accessible (except by implementing workarounds).
Either class IndexTracker should be public or the constructor argument of LuceneIndexMBeanImpl should be LuceneIndexProvider.