6253137: Documentation for NotificationListener's handback parameter is confusing
6368691: javadoc for JMX Descriptors has bugs and is very hard to navigate.
6602699: support for async notification of mbeaninfo update
6759612: [javadoc] EventClient.NOTIFS_LOST has a garbled href to addEventClientListener
6759619: Clarify what EventClient.getEventClientNotificationInfo does
6759622: Clarify what EventClient.getListeners list does
Summary: Documentation fixes, plus simple bugfix for 6759619.
Reviewed-by: dfuchs