PreparedStatement.setString with null - Mailing list pgsql-jdbc

What is this supposed to do?

    PreparedStatement stat = connection.prepareStatement("update table1
set col1 = ?");
    stat.setString(1, null);

Will this make a null value in the database or an empty string?  Do we
have to use the setNull(1, Types.VARCHAR) in order to get a null value
entered?

Thanks,
Tim