Here is the traceback when I restart Jenkins:
hudson.util.IOException2: Unable to read /Users/olivier/.jenkins/jobs/multi/builds/2011-09-06_09-57-54/build.xml
[...]
Caused by: com.thoughtworks.xstream.converters.ConversionException: Cannot deserialize object with new readObject()/writeObject() methods
---- Debugging information ----
class : hudson.matrix.MatrixBuild
required-type : com.google.common.collect.SingletonImmutableList
path : /matrix-build/actions/jenkins.model.InterruptedBuildAction/causes
line number : 12
-------------------------------
And here the section in the XML that seems to be problematic:
<matrix-build>
<actions>
[...]
<jenkins.model.InterruptedBuildAction>
<causes class="com.google.common.collect.SingletonImmutableList" resolves-to="com.google.common.collect.ImmutableList$SerializedForm">
<elements>
<jenkins.model.CauseOfInterruption_-UserInterruption>
<user>admin</user>
</jenkins.model.CauseOfInterruption_-UserInterruption>
</elements>
</causes>
</jenkins.model.InterruptedBuildAction>
</actions>
[...]
</matrix-build>