To get a user;
import com.atlassian.jira.component.ComponentAccessor import com.atlassian.jira.user.util.UserManager userManager = (UserManager) ComponentAccessor.getUserManager(); User user = userManager.getUser('my-user');
To get an issue;
import com.atlassian.jira.ComponentManager import com.atlassian.jira.issue.MutableIssue ComponentManager componentManager = ComponentManager.getInstance() MutableIssue myIssue = componentManager.getIssueManager().getIssueObject('ABC-1234')
To set a reporter for an issue;
myIssue.setReporter(user);
Get a custom field;
CustomField nameCustomField = customFieldManager.getCustomFieldObject('customfield_10123') myIssue.setCustomFieldValue(nameCustomField, "my name")
https://jamieechlin.atlassian.net/wiki/display/GRV/Post+Functions
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