Set nfeed-user field to a particular user

[Veera rdy]

Hello,

I'm trying to set a user to a  nfeed-user field. 

I get the following error:

Cannot cast object '[username(username)]' with class 'java.lang.String' to class 'com.atlassian.jira.user.DelegatingApplicationUser'

Code:

 def customFieldManager = ComponentAccessor.getCustomFieldManager()
 IssueManager issueManager = ComponentAccessor.getOSGiComponentInstanceOfType(IssueManager.class)
 Issue issue = issueManager.getIssueByCurrentKey("ABC-111")
 def Managers = customFieldManager.getCustomFieldObject("customfield_11111")
 ArrayList ManagersVal = ['[username(username)]'] as ArrayList
 DelegatingApplicationUser PManagers = ManagersVal.get(0) as DelegatingApplicationUser;
 IssueManager im = ComponentAccessor.getIssueManager()
 MutableIssue issueMutable = im.getIssueObject(issue.getKey())
 issueMutable.setCustomFieldValue(Managers, PManagers)
 
 def curUser = ComponentAccessor.getJiraAuthenticationContext().getLoggedInUser()
 im.updateIssue(curUser, issueMutable, EventDispatchOption.ISSUE_UPDATED, false);

[Alexey Matveev]

I guess the error line is

DelegatingApplicationUser PManagers = ManagersVal.get(0) as DelegatingApplicationUser;

If you want to receive AppicationUser from the user name you should use

ApplicationUser PmManager = ComponentAccessor.getUserManager().getUserObject("userName")