Getting Incorrect result size in java

I am coming to a problem when quering data and I ge this error: org.springframework.dao.EmptyResultDataAccessException: Incorrect result size: expected 1, actual 0 and I get the results when I print but I get a stacktrace shown below and my query call code below. thanks for the help.

here is my code:

stacktrace:

org.springframework.dao.EmptyResultDataAccessException: Incorrect result size: expected 1, actual 0
        at org.springframework.dao.support.DataAccessUtils.nullableSingleResult(DataAccessUtils.java:97)
        at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:784)
        at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:804)
        at myapppackage.DatabaseAccessObjectImp.getLastSixDigits(DatabaseAccessObjectImp.java:88)
        at myapppackage.Printer.runReport(Printer.java:401)
        at myapppackage.PaystubPrinter.runCheckReport(PaystubPrinter.java:36)
        at myapppackage.PaystubPrinterThread.run(PaystubPrinterThread.java:103)

Code:

    @Override
public String getLastSixDigits(String employeeID) {

 String SQL_GET_LAST_SIX = "SELECT substr(ssn, 4, 9) from app.xr_emp_x_ids@PAYX where employee_id = ? ";

 return jdbcTemplate.queryForObject(SQL_GET_LAST_SIX, new Object(){employeeID}, String.class);
}