Creating new Connections/Statements/ResultSets

Question

Hi,
RDMS = Sybase
JDBC = Jconnect 5.5 obtained from Sybase website
Purpose:
To loop through the program below with different queries and produce
a resultset.
Details:
I have a program that creates a query stores it in a static setter.
The program calls the program below. The program below:
(1) obtains the query from a static getter
(2) creates a connection/statement/resultset
(3) returns to the calling program where
(a) resultset is displayed
(b) calls close() in the program below which closes the
connection/statement/resultset
Problem:
I thought that creating a new connection/statement/resultset
each time the program below is called would work.
The program below returns the correct resultset for the first query
but when called with a different query returns the first resultset that
was generated.
Question:
Do I have to use different objects for the connection/statement/resultset each time the program is called
even though the existing connection/statement/resultset is closed
before a new connection/statement/resultset is created ?
if yes,
I don't how to change the object for connection/statement/resultset
dynamically each time the program below is called.
Any assistance provided would be greatly appreciated !!
Thanks for your time,
YAM-SSM
package ecmutl;
     import java.awt.*;
     import java.sql.*;
     public class DbConnect implements Runnable {     
          public static Thread queryThread = null;     
          public static Font        fntF;
          public static Connection conn = null;
          public static ResultSet rs = null;
          public static Statement stmt = null;      
          public static String nodename = EcmUtlLogicals.getNodeName();
          public static String password =     EcmUtlLogicals.getPassword();
          public String newline = "\n";
          public static String sqlstate;
          public static String message;
          public static String queryThreadDone = "false";
          public static String query = EcmUtlLogicals.getQuery();
          public static String dbname = EcmUtlLogicals.dbname;
          public static String username = EcmUtlLogicals.username;
             public static int SybaseReturnCode; 
          void Connect() {               
                    try {                              
                    Class.forName("com.sybase.jdbc2.jdbc.SybDriver").newInstance();
                       conn = DriverManager.getConnection("jdbc:sybase:Tds:"+nodename+"/"+dbname,username,password);     
               catch (SQLException exc) {
                    sqlstate = exc.getSQLState();          
                    message = exc.getMessage();
                    SybaseReturnCode = exc.getErrorCode();
               catch (InstantiationException iste) {
               catch (ClassNotFoundException cnfe) {
               catch (IllegalAccessException iae) {
               if (queryThread == null) {
                    queryThread = new Thread(this, "Query");
                    queryThread.start();               
               } // close if                 
          } // close Connect method
          public void run() {               
              try {                             
                                 stmt = DbConnect.conn.createStatement();                 
                    rs = stmt.executeQuery(query); 
                    queryThread = null;     
               } // close try
               catch (SQLException sqlex) {
                    sqlstate = sqlex.getSQLState();                     
                    message = sqlex.getMessage();
                    SybaseReturnCode = sqlex.getErrorCode();
                                queryThread = null;
                        } // close catch
                        catch (java.lang.Exception ex) {
                      ex.printStackTrace ();
               } // close catch
               queryThreadDone = "true";
          } // close run method
          static void close() {     
               try {
                     if ( rs != null){
                          rs.close();          
                     if ( stmt != null){
                          stmt.close();
                     if ( conn !=  null){
                          conn.close();     
               } // close try
               catch (SQLException error){     
          }// close close()          
} // close DbConnect class     

Answer 1

Then I'd say you should write a QueryThread object
that extends Thread and takes an SQL statement in its
constructor. In the run method, create a connection,
statement, and result set to run that query, close
them in reverse order when you're done, and provide a
getter to give access to the results. Don't return a
reference to the result set; put the results in a data
structure or CachedRowSet and close out the result set
as soon as you're done with it. ResultSets are
database cursors, which are scarce resources.
With this design, every thread has its own connection
and resources. They can't conflict with each other. -
MODHi MOD,
I finished coding a QueryThread object exactly as you instructed
and IT WORKS !!!!! The calling program calls QueryThread by:
QueryThread qt = new QueryThread(query);
qt.start();
QueryThread code:
package ecmutl;
     import java.awt.*;
     import java.sql.*;
     import java.util.List;
     import java.util.*;
     public class QueryThread extends Thread {
          public static Thread queryThread = null;     
          public static Font        fntF;
          public static Connection conn = null;
          public static ResultSet rs = null;
          public static Statement stmt = null;      
          public static String nodename = EcmUtlLogicals.getNodeName();
          public static String password = EcmUtlLogicals.getPassword();
          public String newline = "\n";
          public static String sqlstate;
          public static String message;
          public static String queryThreadDone = "false";
          public String query;
          public static String dbname = EcmUtlLogicals.dbname;
          public static String username = EcmUtlLogicals.username;     
          public static int SybaseReturnCode;
          public QueryThread(String query) {
               this.query = query;                 
          public void run() {               
               try {              
                    Class.forName("com.sybase.jdbc2.jdbc.SybDriver").newInstance();
                    conn = DriverManager.getConnection("jdbc:sybase:Tds:"+nodename+"/"+dbname,username,password);                                                                                                         
                    stmt = conn.createStatement();                 
                    rs = stmt.executeQuery(query);
                    List resultSetArray = new LinkedList();
                    resultSetArray = new ArrayList(); 
                    if (rs != null) {     
                         int i;
                         ResultSetMetaData rsmd = rs.getMetaData ();
                         int numCols = rsmd.getColumnCount ();
                         for (i=1; i<=numCols; i++) {
                              if (i > 1) resultSetArray.add(",");
                              resultSetArray.add(rsmd.getColumnLabel(i));
                         resultSetArray.add(newline);
                         boolean more = rs.next ();
                         while (more) {
                              for (i=1; i<=numCols; i++) {
                                   if (i > 1) resultSetArray.add(",");
                                   resultSetArray.add(rs.getString(i)); 
                              resultSetArray.add(newline);
                              more = rs.next ();
                         EcmUtlLogicals.setResultSetArray(resultSetArray);
                         if (rs != null){
                              rs.close();
                         if (stmt != null) {
                              stmt.close();
                         if (conn != null) {
                              conn.close();
                    queryThread = null;                                            
               catch (SQLException sqlex) {
                    sqlstate = sqlex.getSQLState();                     
                    message = sqlex.getMessage();
                    SybaseReturnCode = sqlex.getErrorCode();
                    queryThread = null;
               catch (java.lang.Exception ex) {
                                 ex.printStackTrace ();
               queryThreadDone = "true";
     }I have only be using Java for three months. Sometimes one needs a teacher to go along with the APIs.
Thanks for your patience/help/time
YAM-SSM