Attempt to (de-)serialize anonymous class WARN for Jenkins Plugin

[msymons]

After upgrading Jenkins to 2.121.2 LTS and with JavaMelody plugin 1.73.1 installed, the following is seen in Jenkins node logs

<===[JENKINS REMOTING CAPACITY]===>channel started
Remoting version: 3.21
This is a Unix agent
Evacuated stdout
Aug 09, 2018 11:11:50 AM org.jenkinsci.remoting.util.AnonymousClassWarnings warn
WARNING: Attempt to (de-)serialize anonymous class org.jenkinsci.plugins.envinject.EnvInjectComputerListener$2; see: https://jenkins.io/redirect/serialization-of-anonymous-classes/
Agent successfully connected and online

Also seen for Windows nodes connecting via JNLP.

Note link in log to Serialization of anonymous classes wiki page.

[evernat]

I don't think that this is related to the javamelody monitoring plugin. In fact, the class org.jenkinsci.plugins.envinject.EnvInjectComputerListener$2 in the message is from the EnvInject plugin.
And there is already an issue created for the same thing in the EnvInject plugin:
https://issues.jenkins-ci.org/browse/JENKINS-52946

I suppose for now that it is not related to the javamelody monitoring plugin, so closing as invalid.

[msymons]

@evernat, I am afraid that I copied the wrong bit of log! Here's a 2nd attempt, where only the 2nd WARNING is of interest to you...

INFO: Connected
Aug 21, 2018 12:58:04 PM org.jenkinsci.remoting.util.AnonymousClassWarnings warn
WARNING: Attempt to (de-)serialize anonymous class hudson.FilePath$27; see: https://jenkins.io/redirect/serialization-of-anonymous-classes/
Aug 21, 2018 12:58:05 PM org.jenkinsci.remoting.util.AnonymousClassWarnings warn
WARNING: Attempt to (de-)serialize anonymous class net.bull.javamelody.RemoteCallHelper$1; see: https://jenkins.io/redirect/serialization-of-anonymous-classes/

[evernat]

For the first warning, I think that it does not come from the monitoring plugin and that it comes from Jenkins core and that it was fixed. So upgrading your Jenkins server should fix that.

The 2nd warning about net.bull.javamelody.RemoteCallHelper$1 is now fixed by this commit:
jenkinsci/monitoring-plugin@a61d1f0
And it is ready for the next release (1.74), probably early September.
Thanks for the issue.