I stumbled at the same problem today (or at least same stack trace) after a multiple plugin update. There was no way to go in the plugin manager via Web or such, so I had to do it on it by hand on the filesystem.
The offending plugin resulted to be the ssh-slaves as downgrading just that to the previous backed up version solved the problem.
New version creating problem: 1.29.0
My previous version: 1.26
On the upgrade instruction indeed there is a warning:
"Warning: the new version of this plugin claims to use a different settings format than the installed version. Jobs using this plugin may need to be reconfigured, and/or you may not be able to cleanly revert to the prior version without manually restoring old settings. Consult the plugin release notes for details."
But I would still expect it to be caught so I can eventually reconfigure the plugin / jobs via UI.
Jenkins version: both 2.150 and 2.152 behaved the same.
java.runtime.name OpenJDK Runtime Environment