Red Hat
May 21, 2019
by Bela Ban
I'm happy to announce that I just released JGroups 4.1.0!

Why the bump to a new minor version?

I had to make some API changes and - as I'm trying to avoid that in micro releases - I decided to bump the version to 4.1.0. The changes involve removing a few (rather exotic) JChannel constructors, but chances are you've never used any of them anyway. The other change is a signature change in Streamable, where I now throw IOExceptions and ClassNotFoundExceptions instead of simple Exceptions.

Here's a list of the major changes:

GraalVM / Quarkus support

  • JGroups can now be compiled into a native executable using GraalVM's native-image. This is a very cool feature; I've used ProgrammaticUPerf2 to start a member in ~1 millisecond!
  • This means JGroups can now be used by other applications to create native binaries. Not yet very polished, and I'll write a Quarkus extension next, but usable by folks who know GraalVM...
  • I'll blog about the port to GraalVM and the Quarkus extension (once it's ready) next, so stay tuned!
  • https://issues.jboss.org/browse/JGRP-2332
  • https://issues.jboss.org/browse/JGRP-2341

 Parsing of network packets

Diagnostics handler without reflection

  • This is related to the GraalVM port: the default DiagnosticsHandler (used by probe.sh) uses reflection, which is not allowed in GraalVM
  • This additional DiagnosticsHandler can be used instead of the default one when creating a native binary of an application. The advantage is that probe.sh still works, even in a native binary.
  • https://issues.jboss.org/browse/JGRP-2337

RpcDispatcher without reflection

 Probe: support when running under TCP

  • Also required when running on GraalVM: since JGroups currently only supports TCP (MulticastSockets don't currently work on GraalVM), probe.sh needs to be given the address of *one* member, to fetch information about all members
  • https://issues.jboss.org/browse/JGRP-2336

 Change in how IPv4/IPv6 addresses are picked

  • The new algorithm centers around bind_addr defined in the transport (UDP, TCP, TCP_NIO2); the value of this address determines how other addresses (such as loopback, site_local, global, localhost or default values) are resolved.
  • Example: if bind_addr=::1, then all other addresses that are not explicitly defined will be IPv6. If bind_addr=127.0.0.1, the all other addresses will be IPv4 addresses.
  • The advantage of this is that you can run a JGroups stack using IPv4 and another one using IPv6 in the same process!
  • https://issues.jboss.org/browse/JGRP-2343
A complete list of JIRA issues is at https://issues.jboss.org/projects/JGRP/versions/12341388
Please post questions/issues to the mailing list at https://groups.google.com/forum/#!forum/jgroups-dev.

Enjoy!
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