1) try to prevent using SELECT *. That will retrieve all columns of the record. Select only what you need; in this case that would be "SELECT APPL_CD FROM ..."
2) APPL_CD is a string, so
you should enclose it in quotes.
3) you now have mstr_APPL_CD as a literal inside the statement. You need to replace that with the value of the
Java variable; String concatenation should do the trick.
4) I don't think you'll be able to use the Statement after closing it. I'm absolutely sure you can't after closing its connection. Only close these when you're done with them.
5) you should be careful for SQL injection (look it up). Make sure that the APPL_CD column cannot contain any dangerous values. Otherwise use PreparedStatement instead of Statement.