Jenkins executors are not robust against nulls returned by createValue() and createDefaultValue(). Such return value is valid according to Javadoc.

NPE in canTake() procedure kills the executor thread. Unfortunately, Jenkins tries other executors after that => any NPE in canTake() terminates ALL active Jenkins executors.

The initial description from Rotem:

when using jenkins-multijob-plugin and parameter from type “File Parameter” the Jenkins crashes.
When i start to run a Multijob with a multijob phase with values in "Advanced: "parameters", if the next job has a parameter from type “File Parameter” Jenkins is eating up all the executers with - ALL available Build executors are turning into zombies with the status 'Dead ' with the exception:

java.lang.NullPointerException
at hudson.model.ParametersAction.getAssignedLabel(ParametersAction.java:126)
at hudson.model.Queue$Item.getAssignedLabel(Queue.java:1265)
at hudson.model.Node.canTake(Node.java:308)
at hudson.model.Queue$JobOffer.canTake(Queue.java:210)
at hudson.model.Queue.maintain(Queue.java:952)
at hudson.model.Queue.pop(Queue.java:783)
at hudson.model.Executor.grabJob(Executor.java:287)
at hudson.model.Executor.run(Executor.java:208)

Even if at this stage I go to the settings and enlarge the number of Executors, they immediately turn into zombies as well.
When I remove the specific “File Parameter” parameter all works fine.
Please advice.