Update the Value of Custom Fields through the Script Console

import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.event.type.EventDispatchOption
import com.atlassian.jira.issue.fields.CustomField
import groovy.transform.Field

// the issue key to update
@Field final String issueKey = "JRA-1"

// the name of a 'single select list' custom field
final String selectList = "SelectListA"

// the name of a 'multi select list' custom field
final String multiSelectList = "MultiSelectA"

// name of a 'radio button' custom field
final String radioButtonField = "RadioButtons"

// name of a 'check box' custom field
final String checkboxField = "Checkboxes"

// the name of a 'text field' custom field
final String textField = "TextFieldA"

// the name of a 'user picker' custom field
final String userPicker = "UserPicker"

// the name of a 'multi user picker' custom field
final String multiUserPicker = "MultiUserPickerA"

// the name of a 'group picker' custom field
final String groupPicker = "GroupPicker"

// the name of a 'multi group picker' custom field
final String multiGroupPicker = "MultiGroupPicker"

// the name of a 'date and time' custom field
final String dateTimeField = "First DateTime"

// the name of a 'date' custom field
final String dateField = "Date"

// the name of a 'project picker' custom field
final String projectPickerField = "ProjectPicker"

// the name of a 'label' picker custom field
final String labelField = "LabelField"

// name of a 'single version picker' custom field
final String versionField = "VersionPicker"

// change to 'true' if you want to send an email if the update is successful
final boolean sendMail = false

def issueService = ComponentAccessor.issueService
def loggedInUser = ComponentAccessor.jiraAuthenticationContext.loggedInUser
def issue = ComponentAccessor.issueManager.getIssueByCurrentKey(issueKey)

assert issue: "Could not find issue with key $issueKey"

def issueInputParameters = issueService.newIssueInputParameters().with {
    // set custom fields with options (select lists, checkboxes, radio buttons)
    addCustomFieldValue(getSingleCustomFieldByName(selectList).id, *getOptionIdsForFieldByValue(selectList, "BBB"))
    addCustomFieldValue(getSingleCustomFieldByName(multiSelectList).id, *getOptionIdsForFieldByValue(multiSelectList, "BBB", "CCC"))
    addCustomFieldValue(getSingleCustomFieldByName(radioButtonField).id, *getOptionIdsForFieldByValue(radioButtonField, "Yes"))
    addCustomFieldValue(getSingleCustomFieldByName(checkboxField).id, *getOptionIdsForFieldByValue(checkboxField, "Maybe", "Yes"))

    // set text fields
    addCustomFieldValue(getSingleCustomFieldByName(textField).id, "New Value")

    // set user fields
    addCustomFieldValue(getSingleCustomFieldByName(userPicker).id, "bob")
    addCustomFieldValue(getSingleCustomFieldByName(multiUserPicker).id, "bob", "alice")

    // set group fields
    addCustomFieldValue(getSingleCustomFieldByName(groupPicker).id, "jira-users")
    addCustomFieldValue(getSingleCustomFieldByName(multiGroupPicker).id, "jira-users", "jira-administrators")

    // set custom field of type date
    addCustomFieldValue(getSingleCustomFieldByName(dateTimeField).id, "04/Feb/12 8:47 PM")
    addCustomFieldValue(getSingleCustomFieldByName(dateField).id, "04/Feb/12")
}

// set project picker field
def project = ComponentAccessor.projectManager.getProjectObjByKey("SSPA")
assert project: "Could not find project"
issueInputParameters.addCustomFieldValue(getSingleCustomFieldByName(projectPickerField).id, project.id.toString())

// set custom field of type label
issueInputParameters.addCustomFieldValue(getSingleCustomFieldByName(labelField).id, "foo", "bar")

// set custom field of type version
def version = ComponentAccessor.versionManager.getVersions(issue.projectObject).findByName("Version1")
assert version: "Could not find version"
issueInputParameters.addCustomFieldValue(getSingleCustomFieldByName(versionField).id, version.id.toString())

def updateValidationResult = issueService.validateUpdate(loggedInUser, issue.id, issueInputParameters)
assert updateValidationResult.isValid(): updateValidationResult.errorCollection

def issueUpdateResult = issueService.update(loggedInUser, updateValidationResult, EventDispatchOption.ISSUE_UPDATED, sendMail)
assert issueUpdateResult.isValid(): issueUpdateResult.errorCollection

/**
 * Get a custom field given a custom field name.
 * If there are than one custom fields with the same name under the same Context then return the first one.
 * @param fieldName The name of the custom field
 * @param issue The issue to look for that custom field
 * @return the custom field, if that exists
 */
CustomField getSingleCustomFieldByName(String fieldName) {
    def issue = ComponentAccessor.issueManager.getIssueByCurrentKey(issueKey)
    def customField = ComponentAccessor.customFieldManager.getCustomFieldObjects(issue).findByName(fieldName)

    assert customField: "Could not find custom field with name $fieldName"
    customField
}

/**
 * Given a custom field name and option values, retrieve their ids as String
 * @param customFieldName The name of the custom field
 * @param values The values in order to get their ids
 * @return List < String >  The ids of the given values
 */
List getOptionIdsForFieldByValue(String customFieldName, String... values) {
    def issue = ComponentAccessor.issueManager.getIssueByCurrentKey(issueKey)
    def customField = getSingleCustomFieldByName(customFieldName)

    ComponentAccessor.optionsManager.getOptions(customField.getRelevantConfig(issue)).findAll {
        it.value in values.toList()
    }*.optionId*.toString()
}