import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.issue.fields.CustomField
import com.atlassian.jira.issue.CustomFieldManager
import java.sql.Timestamp
def customFieldManager = ComponentAccessor.getCustomFieldManager()
def issue = ComponentAccessor.getIssueManager().getIssueByCurrentKey('xxxx-xxxx')
def months = 1
def dateACF = customFieldManager.getCustomFieldObject("customfield_xxxx")
def dateAValue = issue.getCustomFieldValue(dateACF) as Date
log.warn dateACF
log.warn dateAValue
def dateB = Calendar.getInstance()
dateB.setTime(dateAValue)
dateB.add(Calendar.MONTH, +months)
dateB.getTime()
log.warn dateB.getTime()
LOGS:
2021-09-08 11:44 WARN [runner.ScriptBindingsManager]: EMP Effective Date 2021-09-08 11:44:08,595 WARN [runner.ScriptBindingsManager]: 2021-08-02 00:00:00.0 2021-09-08 11:44:08,596 WARN [runner.ScriptBindingsManager]: Thu Sep 02 00:00:00 MDT 2021