protected Map<String, User> getInternalUsers() {
    final List<User> internalUsers = users.getAllUsers();
    final Map<String, User> internalUsersMap = new HashMap<>();
    LOG.trace("Get all users from Ambari Server.");
    for (User user : internalUsers) {
      internalUsersMap.put(user.getUserName(), user);
    }
    return internalUsersMap;
  }
Creates a map of internal users.

@return map of UserName-User pairs
ambari-server/src/main/java/org/apache/ambari/server/security/ldap/AmbariLdapDataPopulator.java