The workitem getResolver() returns a contributorHandler but there is
no public api to set a resolver. However there is an api to set the
resolution - setResolution2()? What is the difference? I assume that
I should use setResolution2() as oppose to setResolver() which is
private.
Thank you to clarify this.

They are unrelated: The Resolver is the person who resolved the work
item. This attribute is set internally when an work item moves to a
resolved state. The Resolution belongs to the workflow and represents a
more fine-graines qualification of the state/ E.g. Resolution: 'Fixed',
State: 'Resolved'. The resolution can be set when the state is changed
using an action.

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Regards,
Patrick
Jazz Work Item Team