Re: Two of three SQL stmts execute: third results in table does not exist exception

I attempt to collect data from a database three times in one method,
all using one connection. The first two queries execute without any
problem. However, the third fires an sql exception:

java.sql.SQLSyntaxErrorException: Table/View 'TABLENAME' does not
exist.

I connect to the database using a connection class, as follows:

public class MyDBConnection {

    public static final String DRIVER_NAME =
"org.apache.derby.jdbc.ClientDriver";
    public static final String DATABASE_URL = "jdbc:derby://localhost:
1527/cfdb";
    public Connection myConnection;

    public MyDBConnection() {}

     public void init() {
        Class.forName(DRIVER_NAME);
        myConnection =
DriverManager.getConnection(DATABASE_URL,"usnm","pswd");
    }
... [getters and setters deleted]

I then query the database from within a UI constructor like this:

public class MainUCInterface extends javax.swing.JFrame {

    MyDBConnection myConnection = new MyDBConnection();
    Connection con = null;
    Statement stmt = null;
    ResultSet rs = null;

    public MainUCInterface() throws SQLException {
        initComponents();

        myConnection.init();
        con = myConnection.getMyConnection();

        stmt = con.createStatement();
        rs = stmt.executeQuery("select CONTYPEID, CONTYPENAME from
CONTYPES order by CONTYPENAME"); //This query executes fine

        Statement stmt2 = null;
        ResultSet rs2 = null;
        stmt2 = con.createStatement();
        rs2 = stmt2.executeQuery("select CONTYPEID, CONTYPENAME from
CONTYPES where CONTYPEID = " + iConvTyp); //iConvTyp is an integer,
and this query also executes fine.

        ResultSet rs3 = null;
        Statement stmt3 = null;
        stmt3 = con.createStatement();

        String tableName = strConvTyp + "CF";
        String unitName = strConvTyp + "Name";
        String unitID = strConvTyp + "ID";

        String sqlListData = "select " + unitID + ", " + unitName + "
from " + tableName;
        rs3 = stmt3.executeQuery(sqlListData); //This is where the
error occurs. All the strings in stmt3 are fine (correct spelling,
etc.)

A couple of additional notes:

1. The first two queries are on the same table. I tried
reconstructing the third table, and I just finished rebuilding the
whole database from scratch--it didn't help.

2. There is no relational structure to the database. It's just a
group of tables that hold data I need to retrieve to provide
functionality to the app. I don't know if this is a relevant point or
not.

From that, you should be able to get all the information you need.