com.google.api.ads.dfp.axis.v201311.DeactivateCustomFields action =
new com.google.api.ads.dfp.axis.v201311.DeactivateCustomFields();
// Perform action.
UpdateResult result = customFieldService.performCustomFieldAction(
action, statementBuilder.toStatement());
if (result != null && result.getNumChanges() > 0) {
System.out.printf("Number of custom fields deactivated: %d\n", result.getNumChanges());
} else {
System.out.println("No custom fields were deactivated.");