Failed initializing component ThreadPool in protocol UDP

[eitan-rosenberg]

Hello all,

After upgrading org.jgroups:jgroups:jar:5.2.9.Final to version 5.2.10.Final when using new JChannel() I am getting:

Caused by: java.lang.IllegalArgumentException: failed initializing component ThreadPool in protocol UDP: java.lang.IllegalStateException: failed to create virtual thread pool: java.lang.UnsupportedOperationException: Preview Features not enabled, need to run with --enable-preview
at jgroups@5.2.10.Final/org.jgroups.stack.ProtocolStack.lambda$initComponents$7(ProtocolStack.java:861)
at jgroups@5.2.10.Final/org.jgroups.util.Util.forAllComponents(Util.java:3368)
at jgroups@5.2.10.Final/org.jgroups.stack.ProtocolStack.initComponents(ProtocolStack.java:839)
at jgroups@5.2.10.Final/org.jgroups.stack.ProtocolStack.initProtocolStack(ProtocolStack.java:795)
at jgroups@5.2.10.Final/org.jgroups.stack.ProtocolStack.setup(ProtocolStack.java:438)
at jgroups@5.2.10.Final/org.jgroups.JChannel.init(JChannel.java:899)
at jgroups@5.2.10.Final/org.jgroups.JChannel.(JChannel.java:123)
at jgroups@5.2.10.Final/org.jgroups.JChannel.(JChannel.java:105)
at jgroups@5.2.10.Final/org.jgroups.JChannel.(JChannel.java:96)

I see : Preview Features not enabled, need to run with --enable-preview
but I cannot use it, what to do?

Thanks for any response.

[belaban]

OK, so when running under a JDK that has virtual threads available, there's 2 things you can do:

• If you want to use virtual threads, set use_virtual_threads="true" in UDP and use --enable-preview
• If you don't want to use virtual threads, set use_virtual_threads="false" in UDP

If you run in a JVM that doesn't have virtual threads, you don't need to do anything and virtual thread won't (and can't) be used.

[eitan-rosenberg]

Thanks for the quick response,
I use Openjdk 19.0.1, so I use a copy of udp.xml (myUdp.xml).
The new code is: new JChannel("myUdp.xml")
Regards.

p.s. any plans to use Automatic-Module-Name in MANIFEST.MF ? 

[belaban]

I don't know what that is... If it is simple to implement and doesn't complicate things (like multi-release Jars) and you submit a PR, I'd take a look...