in src/main/java/org/apache/sling/serviceusermapping/impl/ServiceUserMapperImpl.java [268:277]
public String getServiceUserID(final Bundle bundle, final String subServiceName) {
final String serviceName = getServiceName(bundle);
final String userId = internalGetUserId(serviceName, subServiceName);
final boolean valid = isValidUser(userId, serviceName, subServiceName, false);
final String result = valid ? userId : null;
log.debug(
"getServiceUserID(bundle {}, subServiceName {}) returns [{}] (raw userId={}, valid={})",
new Object[] { bundle, subServiceName, result, userId, valid });
return result;
}