The auto-create-jms-queues, auto-delete-jms-queues,
auto-create-jms-topics, and auto-delete-jms-topics address settings
were deprecated in ARTEMIS-881 way back in 2016. There's no need to keep
them in the default broker.xml at this point.
JGroups 3.x hasn't been updated in some time now. The last release was
in April 2020 almost 2 years ago. Lots of protocols have been updated
and added and users are wanting to use them. There is also increasing
concern about using older components triggered mainly by other
recently-discovered high-profile vulnerabilities in the wider Open
Source Java community.
This commit bumps JGroups up to the latest release - 5.2.0.Final.
However, there is a cost associated with upgrading.
The old-style properties configuration is no longer supported. I think
it's unlikely that end-users are leveraging this because it is not
exposed via broker.xml. The JGroups XML configuration has been around
for a long time, is widely adopted, and is still supported. I expect
most (if not all) users are using this. However, a handful of tests
needed to be updated and/or removed to deal with this absence.
Some protocols and/or protocol properties are no longer supported. This
means that users may have to change their JGroups stack configurations
when they upgrade. For example, our own clustered-jgroups example had to
be updated or it wouldn't run properly.
MQTT 5 is an OASIS standard which debuted in March 2019. It boasts
numerous improvments over its predecessor (i.e. MQTT 3.1.1) which will
benefit users. These improvements are summarized in the specification
at:
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901293
The specification describes all the behavior necessary for a client or
server to conform. The spec is highlighted with special "normative"
conformance statements which distill the descriptions into concise
terms. The specification provides a helpful summary of all these
statements. See:
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901292
This commit implements all of the mandatory elements from the
specification and provides tests which are identified using the
corresponding normative conformance statement. All normative
conformance statements either have an explicit test or are noted in
comments with an explanation of why an explicit test doesn't exist. See
org.apache.activemq.artemis.tests.integration.mqtt5 for all those
details.
This commit also includes documentation about how to configure
everything related to the new MQTT 5 features.