What is the right syntax for retrieving the last_insert_id() inPostgresql ?

Hi,

I hope I am posting on the right forum.  I googled but I can't find any solution pertaining to my problem.

Could someone know what is the syntext for last_insert_id() in Postgresql for me to insert into my sql execute query?

public int getTutorById() {
        openConnection();
        int tutor_id = 0;
        try {
            Statement stmt3 = connection.createStatement();
            ResultSet rs = stmt3.executeQuery("SELECT last_insert_id() from xtutor");
            {
                while (rs.next()) {
                    tutor_id = rs.getInt(1);                            
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return tutor_id;
    }

org.postgresql.util.PSQLException: ERROR: function last_insert_id() does not exist
  Hint: No function matches the given name and argument types. You might need to add explicit type casts.
  Position: 8
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2440)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2183)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:308)
    at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:441)
    at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:365)
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:307)
    at org.postgresql.jdbc.PgStatement.executeCachedSql(PgStatement.java:293)
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:270)
    at org.postgresql.jdbc.PgStatement.executeQuery(PgStatement.java:224)
    at daoMySql.tutorDAOImpl.getTutorById(tutorDAOImpl.java:202)
    at daoMySql.tutorDAOImpl.getAlltutors(tutorDAOImpl.java:161)
    at business.manager.getAlltutors(manager.java:99)

The generated id is successfully generated by JDBC.

The errors when I tested in out using PGAdmin4 is 

ERROR:  function last_insert_id() does not exist
LINE 1: SELECT last_insert_id() from xtutor;
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
SQL state: 42883
Character: 8

Postgresql 11, Windows 11

Thanks.