It is a follow-up to https://github.com/jenkinsci/maven-plugin/pull/109#pullrequestreview-87462239
According to Javadoc there should be always deleted upon build completion and hence it should be never serialized/deserialized with XStream... But Javadoc is not correct. This action may get to the disk if a whatever logic calls save() on a running Maven build. And I see such cases in PCT which I performed for JEP-200 (e.g. for Config File Provider). It may also happen in production when a Jenkins instance gets force killed with a running Maven build.
I propose to modify "readResolve()" and "writeReplace()" logic in AbstractMavenBuild in order to drop MavenProbeAction when serializing/deserializing objects