Thread: Help Needed with Connection Pooling for Java Swing Based applications - reg.

Help Needed with Connection Pooling for Java Swing Based applications - reg.

From
Shanmugasundaram Doraisamy
Date:
Dear group,

We are having some problems when using JDBC Connection Pool using
Postgrsql Jdbc3PoolingDataSource.

The Pool behaves fine if there is no Swing Component in the Program.
If there is a swing Component ,then the connection seems to be not
returning to the pool and calling for an additional instance of the
class leeds to the creation of fresh Connection objects ,at times it
even exceeds the maximum number allowed in the pool.
If we go for System.exit(0);(Killing) then only the Connection is returned .

But if we comment the swing component line (here in the attached Program
a JOptionPane is Used) then the pool behaves fine.


Herewith Iam attaching a Program which is behaving as detailed.

Any Help is Welcome.

##################################################################


##################################################################

/*
 * ConPool.java
 *
 * Created on 26 March 2003, 11:54
 */

/**
 *
 * @author  naks from vpsd,Erode
 *
 */
import org.postgresql.jdbc3.*;
import java.sql.*;

public class ConPool {

    Jdbc3PoolingDataSource source = null;
    private Connection conn = null;

    /** Creates a new instance of ConPool */
    public ConPool() {

    }

    /** Setting the Pool which intializes the Pool to 2. */
    public void setPool() {
        // DataSource initialization
        System.out.println("setPool()");
        try {
            System.out.println("setting pool");
            // constructs a pool only when source is not assigned.
            // this will prevent problems if the same pool is set more than
            // one time
            if (source == null) {
                source = new Jdbc3PoolingDataSource();
                // DataSource configuration.

        source.setServerName("192.168.0.51");
        source.setDatabaseName("kec_test_pool");
        source.setUser("venbro");
        source.setPassword("venbro");
        source.setMaxConnections(2);


            } else {
                System.out.println("pool is set");
                return;
            }
        } catch (Exception loException) {
            // logger.logToFile(loException);
            loException.printStackTrace();
        }

    } //End of setPool method


    /**
     * Method inserts data to a table "test" which is like
     * create table test (param1 varchar(2),param2 varchar(2)) ;

     */
     public int insertDatas(){

     int count=-1;


      try{

      conn=source.getConnection();

      PreparedStatement st = conn.prepareStatement("INSERT INTO test
values('P1','P2')");

      count = st.executeUpdate();

      st.close();

      conn.commit();
      conn.close();

    }
    catch (SQLException ex) {
       count=0;
      ex.printStackTrace();
    }

    return count;
    }//End of Insert Method


      public static void main(String args[]){


        ConPool cp=new ConPool();
        cp. setPool();
        int sucess_flag=cp.insertDatas();
        System.out.println("Sucess"+sucess_flag);

        /**
          * Upto this level the Connection pooling is working fine .
          * But if this Swing Component is added then it creates new
Connection
          * which is even more than the intial connection of the pool..
         *  We have to kill the application (System.exit(0))to remove
the Connection
         ** But on commenting line :105 "Swingline " the Pool is working
fine..

         */

javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
Swing line 105



    }

}//End of the class
##########################################################################################

###########################################################################################


Re: Help Needed with Connection Pooling for Java Swing Based

From
Barry Lind
Date:
I just ran your test case and everything seems to be working correctly
as far as I can tell.  The program creates one and only one connection
to the database.  I don't see multiple connections created as you are
reporting.

I don't know anything about swing, but it is clear that the code for
swing you have below isn't correct.  Because with this swing call the
program doesn't exit.  It seems the swing code is starting some other
threads that are running and thus the main program doesn't exit until
those threads stop running (and I don't know what swing calls are
necessary to stop the swing threads from running).

So with the swing call in place I have to ctrl-C to stop the app from
running, but from the jdbc side of things everything seems to be working
correctly.

Perhaps I don't understand the problem you are seeing?

thanks,
--Barry


Shanmugasundaram Doraisamy wrote:
> Dear group,
>
> We are having some problems when using JDBC Connection Pool using
> Postgrsql Jdbc3PoolingDataSource.
>
> The Pool behaves fine if there is no Swing Component in the Program.
> If there is a swing Component ,then the connection seems to be not
> returning to the pool and calling for an additional instance of the
> class leeds to the creation of fresh Connection objects ,at times it
> even exceeds the maximum number allowed in the pool.
> If we go for System.exit(0);(Killing) then only the Connection is returned .
>
> But if we comment the swing component line (here in the attached Program
> a JOptionPane is Used) then the pool behaves fine.
>
>
> Herewith Iam attaching a Program which is behaving as detailed.
>
> Any Help is Welcome.
>
> ##################################################################
>
>
> ##################################################################
>
> /*
>  * ConPool.java
>  *
>  * Created on 26 March 2003, 11:54
>  */
>
> /**
>  *
>  * @author  naks from vpsd,Erode
>  *
>  */
> import org.postgresql.jdbc3.*;
> import java.sql.*;
>
> public class ConPool {
>
>     Jdbc3PoolingDataSource source = null;
>     private Connection conn = null;
>
>     /** Creates a new instance of ConPool */
>     public ConPool() {
>
>     }
>
>     /** Setting the Pool which intializes the Pool to 2. */
>     public void setPool() {
>         // DataSource initialization
>         System.out.println("setPool()");
>         try {
>             System.out.println("setting pool");
>             // constructs a pool only when source is not assigned.
>             // this will prevent problems if the same pool is set more than
>             // one time
>             if (source == null) {
>                 source = new Jdbc3PoolingDataSource();
>                 // DataSource configuration.
>
>         source.setServerName("192.168.0.51");
>         source.setDatabaseName("kec_test_pool");
>         source.setUser("venbro");
>         source.setPassword("venbro");
>         source.setMaxConnections(2);
>
>
>             } else {
>                 System.out.println("pool is set");
>                 return;
>             }
>         } catch (Exception loException) {
>             // logger.logToFile(loException);
>             loException.printStackTrace();
>         }
>
>     } //End of setPool method
>
>
>     /**
>      * Method inserts data to a table "test" which is like
>      * create table test (param1 varchar(2),param2 varchar(2)) ;
>
>      */
>      public int insertDatas(){
>
>      int count=-1;
>
>
>       try{
>
>       conn=source.getConnection();
>
>       PreparedStatement st = conn.prepareStatement("INSERT INTO test
> values('P1','P2')");
>
>       count = st.executeUpdate();
>
>       st.close();
>
>       conn.commit();
>       conn.close();
>
>     }
>     catch (SQLException ex) {
>        count=0;
>       ex.printStackTrace();
>     }
>
>     return count;
>     }//End of Insert Method
>
>
>       public static void main(String args[]){
>
>
>         ConPool cp=new ConPool();
>         cp. setPool();
>         int sucess_flag=cp.insertDatas();
>         System.out.println("Sucess"+sucess_flag);
>
>         /**
>           * Upto this level the Connection pooling is working fine .
>           * But if this Swing Component is added then it creates new
> Connection
>           * which is even more than the intial connection of the pool..
>          *  We have to kill the application (System.exit(0))to remove
> the Connection
>          ** But on commenting line :105 "Swingline " the Pool is working
> fine..
>
>          */
>
> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
> Swing line 105
>
>
>
>     }
>
> }//End of the class
> ##########################################################################################
>
> ###########################################################################################
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>


Re: Help Needed with Connection Pooling for Java Swing Based

From
Derek S
Date:
Instantiating any Swing component does in fact start a new thread - the
AWT Event Dispatch thread.  My experience with it has been that this
thread quite often doesn't terminate the way you might expect when the
main method ends.  This is a well known issue that Swing and AWT
programmers simply have to deal with and has absolutely nothing to do
with JDBC.  Generally speaking, all Swing/AWT based applications call
System.exit when they are finished doing whatever it is they do in order
to ensure that the AWT Event Dispatch thread shuts down properly.

Barry Lind wrote:

> I just ran your test case and everything seems to be working correctly
> as far as I can tell.  The program creates one and only one connection
> to the database.  I don't see multiple connections created as you are
> reporting.
>
> I don't know anything about swing, but it is clear that the code for
> swing you have below isn't correct.  Because with this swing call the
> program doesn't exit.  It seems the swing code is starting some other
> threads that are running and thus the main program doesn't exit until
> those threads stop running (and I don't know what swing calls are
> necessary to stop the swing threads from running).
>
> So with the swing call in place I have to ctrl-C to stop the app from
> running, but from the jdbc side of things everything seems to be
> working correctly.
>
> Perhaps I don't understand the problem you are seeing?
>
> thanks,
> --Barry
>
>
> Shanmugasundaram Doraisamy wrote:
>
>> Dear group,
>>
>> We are having some problems when using JDBC Connection Pool using
>> Postgrsql Jdbc3PoolingDataSource.
>>
>> The Pool behaves fine if there is no Swing Component in the Program.
>> If there is a swing Component ,then the connection seems to be not
>> returning to the pool and calling for an additional instance of the
>> class leeds to the creation of fresh Connection objects ,at times it
>> even exceeds the maximum number allowed in the pool.
>> If we go for System.exit(0);(Killing) then only the Connection is
>> returned .
>>
>> But if we comment the swing component line (here in the attached
>> Program a JOptionPane is Used) then the pool behaves fine.
>>
>>
>> Herewith Iam attaching a Program which is behaving as detailed.
>>
>> Any Help is Welcome.
>>
>> ##################################################################
>>
>>
>> ##################################################################
>>
>> /*
>>  * ConPool.java
>>  *
>>  * Created on 26 March 2003, 11:54
>>  */
>>
>> /**
>>  *
>>  * @author  naks from vpsd,Erode
>>  *   */
>> import org.postgresql.jdbc3.*;
>> import java.sql.*;
>>
>> public class ConPool {
>>        Jdbc3PoolingDataSource source = null;
>>     private Connection conn = null;
>>        /** Creates a new instance of ConPool */
>>     public ConPool() {
>>            }
>>        /** Setting the Pool which intializes the Pool to 2. */
>>     public void setPool() {
>>         // DataSource initialization
>>         System.out.println("setPool()");
>>         try {
>>             System.out.println("setting pool");
>>             // constructs a pool only when source is not assigned.
>>             // this will prevent problems if the same pool is set
>> more than
>>             // one time
>>             if (source == null) {
>>                 source = new Jdbc3PoolingDataSource();
>>                 // DataSource configuration.
>>                       source.setServerName("192.168.0.51");
>>         source.setDatabaseName("kec_test_pool");
>>         source.setUser("venbro");
>>         source.setPassword("venbro");
>>         source.setMaxConnections(2);
>>                                } else {
>>                 System.out.println("pool is set");
>>                 return;
>>             }
>>         } catch (Exception loException) {
>>             // logger.logToFile(loException);
>>             loException.printStackTrace();
>>         }
>>
>>     } //End of setPool method
>>           /**
>>      * Method inserts data to a table "test" which is like
>>      * create table test (param1 varchar(2),param2 varchar(2)) ;
>>          */
>>      public int insertDatas(){
>>            int count=-1;
>>              try{
>>                conn=source.getConnection();
>>
>>       PreparedStatement st = conn.prepareStatement("INSERT INTO test
>> values('P1','P2')");
>>            count = st.executeUpdate();
>>
>>       st.close();
>>            conn.commit();
>>       conn.close();
>>          }
>>     catch (SQLException ex) {
>>        count=0;
>>       ex.printStackTrace();
>>     }
>>        return count;
>>     }//End of Insert Method
>>               public static void main(String args[]){
>>                       ConPool cp=new ConPool();
>>         cp. setPool();
>>         int sucess_flag=cp.insertDatas();
>>         System.out.println("Sucess"+sucess_flag);
>>                /**
>>           * Upto this level the Connection pooling is working fine .
>>           * But if this Swing Component is added then it creates new
>> Connection
>>           * which is even more than the intial connection of the pool..
>>          *  We have to kill the application (System.exit(0))to remove
>> the Connection
>>          ** But on commenting line :105 "Swingline " the Pool is
>> working fine..
>>                  */
>>
>> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
>> Swing line 105
>>
>>     }
>>
>> }//End of the class
>> ##########################################################################################
>>
>> ###########################################################################################
>>
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 3: if posting/reading through Usenet, please send an appropriate
>> subscribe-nomail command to majordomo@postgresql.org so that your
>> message can get through to the mailing list cleanly
>>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
> http://www.postgresql.org/docs/faqs/FAQ.html
>


Re: Help Needed with Connection Pooling for Java Swing Based

From
"Scot P. Floess"
Date:
Derek:

Are you sure instantiating a Swing component launches a new thread?
Simply instantiating 2 JButtons will launch 2 threads?  I don't think
that is the case.

Derek S wrote:

> Instantiating any Swing component does in fact start a new thread -
> the AWT Event Dispatch thread.  My experience with it has been that
> this thread quite often doesn't terminate the way you might expect
> when the main method ends.  This is a well known issue that Swing and
> AWT programmers simply have to deal with and has absolutely nothing to
> do with JDBC.  Generally speaking, all Swing/AWT based applications
> call System.exit when they are finished doing whatever it is they do
> in order to ensure that the AWT Event Dispatch thread shuts down
> properly.
>
> Barry Lind wrote:
>
>> I just ran your test case and everything seems to be working
>> correctly as far as I can tell.  The program creates one and only one
>> connection to the database.  I don't see multiple connections created
>> as you are reporting.
>>
>> I don't know anything about swing, but it is clear that the code for
>> swing you have below isn't correct.  Because with this swing call the
>> program doesn't exit.  It seems the swing code is starting some other
>> threads that are running and thus the main program doesn't exit until
>> those threads stop running (and I don't know what swing calls are
>> necessary to stop the swing threads from running).
>>
>> So with the swing call in place I have to ctrl-C to stop the app from
>> running, but from the jdbc side of things everything seems to be
>> working correctly.
>>
>> Perhaps I don't understand the problem you are seeing?
>>
>> thanks,
>> --Barry
>>
>>
>> Shanmugasundaram Doraisamy wrote:
>>
>>> Dear group,
>>>
>>> We are having some problems when using JDBC Connection Pool using
>>> Postgrsql Jdbc3PoolingDataSource.
>>>
>>> The Pool behaves fine if there is no Swing Component in the Program.
>>> If there is a swing Component ,then the connection seems to be not
>>> returning to the pool and calling for an additional instance of the
>>> class leeds to the creation of fresh Connection objects ,at times it
>>> even exceeds the maximum number allowed in the pool.
>>> If we go for System.exit(0);(Killing) then only the Connection is
>>> returned .
>>>
>>> But if we comment the swing component line (here in the attached
>>> Program a JOptionPane is Used) then the pool behaves fine.
>>>
>>>
>>> Herewith Iam attaching a Program which is behaving as detailed.
>>>
>>> Any Help is Welcome.
>>>
>>> ##################################################################
>>>
>>>
>>> ##################################################################
>>>
>>> /*
>>>  * ConPool.java
>>>  *
>>>  * Created on 26 March 2003, 11:54
>>>  */
>>>
>>> /**
>>>  *
>>>  * @author  naks from vpsd,Erode
>>>  *   */
>>> import org.postgresql.jdbc3.*;
>>> import java.sql.*;
>>>
>>> public class ConPool {
>>>        Jdbc3PoolingDataSource source = null;
>>>     private Connection conn = null;
>>>        /** Creates a new instance of ConPool */
>>>     public ConPool() {
>>>            }
>>>        /** Setting the Pool which intializes the Pool to 2. */
>>>     public void setPool() {
>>>         // DataSource initialization
>>>         System.out.println("setPool()");
>>>         try {
>>>             System.out.println("setting pool");
>>>             // constructs a pool only when source is not assigned.
>>>             // this will prevent problems if the same pool is set
>>> more than
>>>             // one time
>>>             if (source == null) {
>>>                 source = new Jdbc3PoolingDataSource();
>>>                 // DataSource configuration.
>>>                       source.setServerName("192.168.0.51");
>>>         source.setDatabaseName("kec_test_pool");
>>>         source.setUser("venbro");
>>>         source.setPassword("venbro");
>>>         source.setMaxConnections(2);
>>>                                } else {
>>>                 System.out.println("pool is set");
>>>                 return;
>>>             }
>>>         } catch (Exception loException) {
>>>             // logger.logToFile(loException);
>>>             loException.printStackTrace();
>>>         }
>>>
>>>     } //End of setPool method
>>>           /**
>>>      * Method inserts data to a table "test" which is like
>>>      * create table test (param1 varchar(2),param2 varchar(2)) ;
>>>          */
>>>      public int insertDatas(){
>>>            int count=-1;
>>>              try{
>>>                conn=source.getConnection();
>>>
>>>       PreparedStatement st = conn.prepareStatement("INSERT INTO test
>>> values('P1','P2')");
>>>            count = st.executeUpdate();
>>>
>>>       st.close();
>>>            conn.commit();
>>>       conn.close();
>>>          }
>>>     catch (SQLException ex) {
>>>        count=0;
>>>       ex.printStackTrace();
>>>     }
>>>        return count;
>>>     }//End of Insert Method
>>>               public static void main(String args[]){
>>>                       ConPool cp=new ConPool();
>>>         cp. setPool();
>>>         int sucess_flag=cp.insertDatas();
>>>         System.out.println("Sucess"+sucess_flag);
>>>                /**
>>>           * Upto this level the Connection pooling is working fine .
>>>           * But if this Swing Component is added then it creates new
>>> Connection
>>>           * which is even more than the intial connection of the pool..
>>>          *  We have to kill the application (System.exit(0))to
>>> remove the Connection
>>>          ** But on commenting line :105 "Swingline " the Pool is
>>> working fine..
>>>                  */
>>>
>>> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
>>> Swing line 105
>>>                 }
>>>
>>> }//End of the class
>>> ##########################################################################################
>>>
>>> ###########################################################################################
>>>
>>>
>>> ---------------------------(end of
>>> broadcast)---------------------------
>>> TIP 3: if posting/reading through Usenet, please send an appropriate
>>> subscribe-nomail command to majordomo@postgresql.org so that your
>>> message can get through to the mailing list cleanly
>>>
>>
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 5: Have you checked our extensive FAQ?
>>
>> http://www.postgresql.org/docs/faqs/FAQ.html
>>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo@postgresql.org so that your
> message can get through to the mailing list cleanly
>

--
Scot P. Floess - 27 Lake Royale - Louisburg, NC  27549 - 252-478-8087

Open Source Home Page
--------------------------------------
http://javapim.sourceforge.net
http://jplate.sourceforge.net
http://jwaretechniques.sourceforge.net

Open Source Project Host
-----------------------------------------------
http://sourceforge.net/projects/javapim
http://sourceforge.net/projects/jplate
http://sourceforge.net/projects/jwaretechniques


Re: Help Needed with Connection Pooling for Java Swing Based

From
Derek S
Date:
Pardon my inaccuracy.  I should have said "Realizing" instead of
instantiating.  "Realizing" is the name that the AWT developers gave to
the process  (which is encapsulated in the AWT's component
implementation) of actually allocating the system resources needed to
display the GUI widgets.  Typically, it happens when you call pack or
setVisible(true) on a Window, Frame or Dialog. When a component is
realized, it checks to see if the dispatcher thread is running, and if
not, starts it.  Depending on what you're using, it may also start other
threads to support features like the Pluggable Look and Feel and so on.
As far as I know, it's only possible to have one AWT Event Dispatch thread.

Bringing us back to the original topic, Once the AWT threads are
running, it's basically hit-or-miss whether the app will stop unless
System.exit is explicitly called or you set the default close operation
on your frame to EXIT_ON_CLOSE (which just calls System.exit for you),
so this has nothing to do with JDBC or PostgreSQL's driver.

Scot P. Floess wrote:

> Derek:
>
> Are you sure instantiating a Swing component launches a new thread?
> Simply instantiating 2 JButtons will launch 2 threads?  I don't think
> that is the case.
>
> Derek S wrote:
>
>> Instantiating any Swing component does in fact start a new thread -
>> the AWT Event Dispatch thread.  My experience with it has been that
>> this thread quite often doesn't terminate the way you might expect
>> when the main method ends.  This is a well known issue that Swing and
>> AWT programmers simply have to deal with and has absolutely nothing
>> to do with JDBC.  Generally speaking, all Swing/AWT based
>> applications call System.exit when they are finished doing whatever
>> it is they do in order to ensure that the AWT Event Dispatch thread
>> shuts down properly.
>>
>> Barry Lind wrote:
>>
>>> I just ran your test case and everything seems to be working
>>> correctly as far as I can tell.  The program creates one and only
>>> one connection to the database.  I don't see multiple connections
>>> created as you are reporting.
>>>
>>> I don't know anything about swing, but it is clear that the code for
>>> swing you have below isn't correct.  Because with this swing call
>>> the program doesn't exit.  It seems the swing code is starting some
>>> other threads that are running and thus the main program doesn't
>>> exit until those threads stop running (and I don't know what swing
>>> calls are necessary to stop the swing threads from running).
>>>
>>> So with the swing call in place I have to ctrl-C to stop the app
>>> from running, but from the jdbc side of things everything seems to
>>> be working correctly.
>>>
>>> Perhaps I don't understand the problem you are seeing?
>>>
>>> thanks,
>>> --Barry
>>>
>>>
>>> Shanmugasundaram Doraisamy wrote:
>>>
>>>> Dear group,
>>>>
>>>> We are having some problems when using JDBC Connection Pool using
>>>> Postgrsql Jdbc3PoolingDataSource.
>>>>
>>>> The Pool behaves fine if there is no Swing Component in the Program.
>>>> If there is a swing Component ,then the connection seems to be not
>>>> returning to the pool and calling for an additional instance of the
>>>> class leeds to the creation of fresh Connection objects ,at times
>>>> it even exceeds the maximum number allowed in the pool.
>>>> If we go for System.exit(0);(Killing) then only the Connection is
>>>> returned .
>>>>
>>>> But if we comment the swing component line (here in the attached
>>>> Program a JOptionPane is Used) then the pool behaves fine.
>>>>
>>>>
>>>> Herewith Iam attaching a Program which is behaving as detailed.
>>>>
>>>> Any Help is Welcome.
>>>>
>>>> ##################################################################
>>>>
>>>>
>>>> ##################################################################
>>>>
>>>> /*
>>>>  * ConPool.java
>>>>  *
>>>>  * Created on 26 March 2003, 11:54
>>>>  */
>>>>
>>>> /**
>>>>  *
>>>>  * @author  naks from vpsd,Erode
>>>>  *   */
>>>> import org.postgresql.jdbc3.*;
>>>> import java.sql.*;
>>>>
>>>> public class ConPool {
>>>>        Jdbc3PoolingDataSource source = null;
>>>>     private Connection conn = null;
>>>>        /** Creates a new instance of ConPool */
>>>>     public ConPool() {
>>>>            }
>>>>        /** Setting the Pool which intializes the Pool to 2. */
>>>>     public void setPool() {
>>>>         // DataSource initialization
>>>>         System.out.println("setPool()");
>>>>         try {
>>>>             System.out.println("setting pool");
>>>>             // constructs a pool only when source is not assigned.
>>>>             // this will prevent problems if the same pool is set
>>>> more than
>>>>             // one time
>>>>             if (source == null) {
>>>>                 source = new Jdbc3PoolingDataSource();
>>>>                 // DataSource configuration.
>>>>                       source.setServerName("192.168.0.51");
>>>>         source.setDatabaseName("kec_test_pool");
>>>>         source.setUser("venbro");
>>>>         source.setPassword("venbro");
>>>>         source.setMaxConnections(2);
>>>>                                } else {
>>>>                 System.out.println("pool is set");
>>>>                 return;
>>>>             }
>>>>         } catch (Exception loException) {
>>>>             // logger.logToFile(loException);
>>>>             loException.printStackTrace();
>>>>         }
>>>>
>>>>     } //End of setPool method
>>>>           /**
>>>>      * Method inserts data to a table "test" which is like
>>>>      * create table test (param1 varchar(2),param2 varchar(2)) ;
>>>>          */
>>>>      public int insertDatas(){
>>>>            int count=-1;
>>>>              try{
>>>>                conn=source.getConnection();
>>>>
>>>>       PreparedStatement st = conn.prepareStatement("INSERT INTO
>>>> test values('P1','P2')");
>>>>            count = st.executeUpdate();
>>>>
>>>>       st.close();
>>>>            conn.commit();
>>>>       conn.close();
>>>>          }
>>>>     catch (SQLException ex) {
>>>>        count=0;
>>>>       ex.printStackTrace();
>>>>     }
>>>>        return count;
>>>>     }//End of Insert Method
>>>>               public static void main(String args[]){
>>>>                       ConPool cp=new ConPool();
>>>>         cp. setPool();
>>>>         int sucess_flag=cp.insertDatas();
>>>>         System.out.println("Sucess"+sucess_flag);
>>>>                /**
>>>>           * Upto this level the Connection pooling is working fine .
>>>>           * But if this Swing Component is added then it creates
>>>> new Connection
>>>>           * which is even more than the intial connection of the
>>>> pool..
>>>>          *  We have to kill the application (System.exit(0))to
>>>> remove the Connection
>>>>          ** But on commenting line :105 "Swingline " the Pool is
>>>> working fine..
>>>>                  */
>>>>
>>>> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
>>>> Swing line 105
>>>>                 }
>>>>
>>>> }//End of the class
>>>> ##########################################################################################
>>>>
>>>> ###########################################################################################
>>>>
>>>>
>>>> ---------------------------(end of
>>>> broadcast)---------------------------
>>>> TIP 3: if posting/reading through Usenet, please send an appropriate
>>>> subscribe-nomail command to majordomo@postgresql.org so that your
>>>> message can get through to the mailing list cleanly
>>>>
>>>
>>>
>>> ---------------------------(end of
>>> broadcast)---------------------------
>>> TIP 5: Have you checked our extensive FAQ?
>>>
>>> http://www.postgresql.org/docs/faqs/FAQ.html
>>>
>>
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 3: if posting/reading through Usenet, please send an appropriate
>> subscribe-nomail command to majordomo@postgresql.org so that your
>> message can get through to the mailing list cleanly
>>
>


Re: Help Needed with Connection Pooling for Java Swing Based

From
"Scot P. Floess"
Date:
Derek:

I see what you mean.

Regarding needing to call System.exit...my guess is the Swing/AWT
threads are user threads (as opposed to daemon) and that is why one must
call System.exit()...

Scot

Derek S wrote:

> Pardon my inaccuracy.  I should have said "Realizing" instead of
> instantiating.  "Realizing" is the name that the AWT developers gave
> to the process  (which is encapsulated in the AWT's component
> implementation) of actually allocating the system resources needed to
> display the GUI widgets.  Typically, it happens when you call pack or
> setVisible(true) on a Window, Frame or Dialog. When a component is
> realized, it checks to see if the dispatcher thread is running, and if
> not, starts it.  Depending on what you're using, it may also start
> other threads to support features like the Pluggable Look and Feel and
> so on.  As far as I know, it's only possible to have one AWT Event
> Dispatch thread.
>
> Bringing us back to the original topic, Once the AWT threads are
> running, it's basically hit-or-miss whether the app will stop unless
> System.exit is explicitly called or you set the default close
> operation on your frame to EXIT_ON_CLOSE (which just calls System.exit
> for you), so this has nothing to do with JDBC or PostgreSQL's driver.
>
> Scot P. Floess wrote:
>
>> Derek:
>>
>> Are you sure instantiating a Swing component launches a new thread?
>> Simply instantiating 2 JButtons will launch 2 threads?  I don't think
>> that is the case.
>>
>> Derek S wrote:
>>
>>> Instantiating any Swing component does in fact start a new thread -
>>> the AWT Event Dispatch thread.  My experience with it has been that
>>> this thread quite often doesn't terminate the way you might expect
>>> when the main method ends.  This is a well known issue that Swing
>>> and AWT programmers simply have to deal with and has absolutely
>>> nothing to do with JDBC.  Generally speaking, all Swing/AWT based
>>> applications call System.exit when they are finished doing whatever
>>> it is they do in order to ensure that the AWT Event Dispatch thread
>>> shuts down properly.
>>>
>>> Barry Lind wrote:
>>>
>>>> I just ran your test case and everything seems to be working
>>>> correctly as far as I can tell.  The program creates one and only
>>>> one connection to the database.  I don't see multiple connections
>>>> created as you are reporting.
>>>>
>>>> I don't know anything about swing, but it is clear that the code
>>>> for swing you have below isn't correct.  Because with this swing
>>>> call the program doesn't exit.  It seems the swing code is starting
>>>> some other threads that are running and thus the main program
>>>> doesn't exit until those threads stop running (and I don't know
>>>> what swing calls are necessary to stop the swing threads from
>>>> running).
>>>>
>>>> So with the swing call in place I have to ctrl-C to stop the app
>>>> from running, but from the jdbc side of things everything seems to
>>>> be working correctly.
>>>>
>>>> Perhaps I don't understand the problem you are seeing?
>>>>
>>>> thanks,
>>>> --Barry
>>>>
>>>>
>>>> Shanmugasundaram Doraisamy wrote:
>>>>
>>>>> Dear group,
>>>>>
>>>>> We are having some problems when using JDBC Connection Pool using
>>>>> Postgrsql Jdbc3PoolingDataSource.
>>>>>
>>>>> The Pool behaves fine if there is no Swing Component in the Program.
>>>>> If there is a swing Component ,then the connection seems to be not
>>>>> returning to the pool and calling for an additional instance of
>>>>> the class leeds to the creation of fresh Connection objects ,at
>>>>> times it even exceeds the maximum number allowed in the pool.
>>>>> If we go for System.exit(0);(Killing) then only the Connection is
>>>>> returned .
>>>>>
>>>>> But if we comment the swing component line (here in the attached
>>>>> Program a JOptionPane is Used) then the pool behaves fine.
>>>>>
>>>>>
>>>>> Herewith Iam attaching a Program which is behaving as detailed.
>>>>>
>>>>> Any Help is Welcome.
>>>>>
>>>>> ##################################################################
>>>>>
>>>>>
>>>>> ##################################################################
>>>>>
>>>>> /*
>>>>>  * ConPool.java
>>>>>  *
>>>>>  * Created on 26 March 2003, 11:54
>>>>>  */
>>>>>
>>>>> /**
>>>>>  *
>>>>>  * @author  naks from vpsd,Erode
>>>>>  *   */
>>>>> import org.postgresql.jdbc3.*;
>>>>> import java.sql.*;
>>>>>
>>>>> public class ConPool {
>>>>>        Jdbc3PoolingDataSource source = null;
>>>>>     private Connection conn = null;
>>>>>        /** Creates a new instance of ConPool */
>>>>>     public ConPool() {
>>>>>            }
>>>>>        /** Setting the Pool which intializes the Pool to 2. */
>>>>>     public void setPool() {
>>>>>         // DataSource initialization
>>>>>         System.out.println("setPool()");
>>>>>         try {
>>>>>             System.out.println("setting pool");
>>>>>             // constructs a pool only when source is not assigned.
>>>>>             // this will prevent problems if the same pool is set
>>>>> more than
>>>>>             // one time
>>>>>             if (source == null) {
>>>>>                 source = new Jdbc3PoolingDataSource();
>>>>>                 // DataSource configuration.
>>>>>                       source.setServerName("192.168.0.51");
>>>>>         source.setDatabaseName("kec_test_pool");
>>>>>         source.setUser("venbro");
>>>>>         source.setPassword("venbro");
>>>>>         source.setMaxConnections(2);
>>>>>                                } else {
>>>>>                 System.out.println("pool is set");
>>>>>                 return;
>>>>>             }
>>>>>         } catch (Exception loException) {
>>>>>             // logger.logToFile(loException);
>>>>>             loException.printStackTrace();
>>>>>         }
>>>>>
>>>>>     } //End of setPool method
>>>>>           /**
>>>>>      * Method inserts data to a table "test" which is like
>>>>>      * create table test (param1 varchar(2),param2 varchar(2)) ;
>>>>>          */
>>>>>      public int insertDatas(){
>>>>>            int count=-1;
>>>>>              try{
>>>>>                conn=source.getConnection();
>>>>>
>>>>>       PreparedStatement st = conn.prepareStatement("INSERT INTO
>>>>> test values('P1','P2')");
>>>>>            count = st.executeUpdate();
>>>>>
>>>>>       st.close();
>>>>>            conn.commit();
>>>>>       conn.close();
>>>>>          }
>>>>>     catch (SQLException ex) {
>>>>>        count=0;
>>>>>       ex.printStackTrace();
>>>>>     }
>>>>>        return count;
>>>>>     }//End of Insert Method
>>>>>               public static void main(String args[]){
>>>>>                       ConPool cp=new ConPool();
>>>>>         cp. setPool();
>>>>>         int sucess_flag=cp.insertDatas();
>>>>>         System.out.println("Sucess"+sucess_flag);
>>>>>                /**
>>>>>           * Upto this level the Connection pooling is working fine .
>>>>>           * But if this Swing Component is added then it creates
>>>>> new Connection
>>>>>           * which is even more than the intial connection of the
>>>>> pool..
>>>>>          *  We have to kill the application (System.exit(0))to
>>>>> remove the Connection
>>>>>          ** But on commenting line :105 "Swingline " the Pool is
>>>>> working fine..
>>>>>                  */
>>>>>
>>>>> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
>>>>> Swing line 105
>>>>>                 }
>>>>>
>>>>> }//End of the class
>>>>> ##########################################################################################
>>>>>
>>>>> ###########################################################################################
>>>>>
>>>>>
>>>>> ---------------------------(end of
>>>>> broadcast)---------------------------
>>>>> TIP 3: if posting/reading through Usenet, please send an appropriate
>>>>> subscribe-nomail command to majordomo@postgresql.org so that your
>>>>> message can get through to the mailing list cleanly
>>>>>
>>>>
>>>>
>>>> ---------------------------(end of
>>>> broadcast)---------------------------
>>>> TIP 5: Have you checked our extensive FAQ?
>>>>
>>>> http://www.postgresql.org/docs/faqs/FAQ.html
>>>>
>>>
>>>
>>> ---------------------------(end of
>>> broadcast)---------------------------
>>> TIP 3: if posting/reading through Usenet, please send an appropriate
>>> subscribe-nomail command to majordomo@postgresql.org so that your
>>> message can get through to the mailing list cleanly
>>>
>>
>
>

--
Scot P. Floess - 27 Lake Royale - Louisburg, NC  27549 - 252-478-8087

Open Source Home Page
--------------------------------------
http://javapim.sourceforge.net
http://jplate.sourceforge.net
http://jwaretechniques.sourceforge.net

Open Source Project Host
-----------------------------------------------
http://sourceforge.net/projects/javapim
http://sourceforge.net/projects/jplate
http://sourceforge.net/projects/jwaretechniques


Re: Help Needed with Connection Pooling for Java Swing Based

From
Shanmugasundaram Doraisamy
Date:
Dear Derek, Scott & Barry,
           Thank you for your replies.  But, when I give the system.exit call
the whole application is closed.  This is not what I want to do.  I just
want to close only that particular form/ window alone and return the
connection to the pool.  Please let me know how this can be achieved.
Thanking you,

Yours sincerely,

Shan.

On Thu, 2003-03-27 at 04:09, Scot P. Floess wrote:
> Derek:
>
> I see what you mean.
>
> Regarding needing to call System.exit...my guess is the Swing/AWT
> threads are user threads (as opposed to daemon) and that is why one must
> call System.exit()...
>
> Scot
>
> Derek S wrote:
>
> > Pardon my inaccuracy.  I should have said "Realizing" instead of
> > instantiating.  "Realizing" is the name that the AWT developers gave
> > to the process  (which is encapsulated in the AWT's component
> > implementation) of actually allocating the system resources needed to
> > display the GUI widgets.  Typically, it happens when you call pack or
> > setVisible(true) on a Window, Frame or Dialog. When a component is
> > realized, it checks to see if the dispatcher thread is running, and if
> > not, starts it.  Depending on what you're using, it may also start
> > other threads to support features like the Pluggable Look and Feel and
> > so on.  As far as I know, it's only possible to have one AWT Event
> > Dispatch thread.
> >
> > Bringing us back to the original topic, Once the AWT threads are
> > running, it's basically hit-or-miss whether the app will stop unless
> > System.exit is explicitly called or you set the default close
> > operation on your frame to EXIT_ON_CLOSE (which just calls System.exit
> > for you), so this has nothing to do with JDBC or PostgreSQL's driver.
> >
> > Scot P. Floess wrote:
> >
> >> Derek:
> >>
> >> Are you sure instantiating a Swing component launches a new thread?
> >> Simply instantiating 2 JButtons will launch 2 threads?  I don't think
> >> that is the case.
> >>
> >> Derek S wrote:
> >>
> >>> Instantiating any Swing component does in fact start a new thread -
> >>> the AWT Event Dispatch thread.  My experience with it has been that
> >>> this thread quite often doesn't terminate the way you might expect
> >>> when the main method ends.  This is a well known issue that Swing
> >>> and AWT programmers simply have to deal with and has absolutely
> >>> nothing to do with JDBC.  Generally speaking, all Swing/AWT based
> >>> applications call System.exit when they are finished doing whatever
> >>> it is they do in order to ensure that the AWT Event Dispatch thread
> >>> shuts down properly.
> >>>
> >>> Barry Lind wrote:
> >>>
> >>>> I just ran your test case and everything seems to be working
> >>>> correctly as far as I can tell.  The program creates one and only
> >>>> one connection to the database.  I don't see multiple connections
> >>>> created as you are reporting.
> >>>>
> >>>> I don't know anything about swing, but it is clear that the code
> >>>> for swing you have below isn't correct.  Because with this swing
> >>>> call the program doesn't exit.  It seems the swing code is starting
> >>>> some other threads that are running and thus the main program
> >>>> doesn't exit until those threads stop running (and I don't know
> >>>> what swing calls are necessary to stop the swing threads from
> >>>> running).
> >>>>
> >>>> So with the swing call in place I have to ctrl-C to stop the app
> >>>> from running, but from the jdbc side of things everything seems to
> >>>> be working correctly.
> >>>>
> >>>> Perhaps I don't understand the problem you are seeing?
> >>>>
> >>>> thanks,
> >>>> --Barry
> >>>>
> >>>>
> >>>> Shanmugasundaram Doraisamy wrote:
> >>>>
> >>>>> Dear group,
> >>>>>
> >>>>> We are having some problems when using JDBC Connection Pool using
> >>>>> Postgrsql Jdbc3PoolingDataSource.
> >>>>>
> >>>>> The Pool behaves fine if there is no Swing Component in the Program.
> >>>>> If there is a swing Component ,then the connection seems to be not
> >>>>> returning to the pool and calling for an additional instance of
> >>>>> the class leeds to the creation of fresh Connection objects ,at
> >>>>> times it even exceeds the maximum number allowed in the pool.
> >>>>> If we go for System.exit(0);(Killing) then only the Connection is
> >>>>> returned .
> >>>>>
> >>>>> But if we comment the swing component line (here in the attached
> >>>>> Program a JOptionPane is Used) then the pool behaves fine.
> >>>>>
> >>>>>
> >>>>> Herewith Iam attaching a Program which is behaving as detailed.
> >>>>>
> >>>>> Any Help is Welcome.
> >>>>>
> >>>>> ##################################################################
> >>>>>
> >>>>>
> >>>>> ##################################################################
> >>>>>
> >>>>> /*
> >>>>>  * ConPool.java
> >>>>>  *
> >>>>>  * Created on 26 March 2003, 11:54
> >>>>>  */
> >>>>>
> >>>>> /**
> >>>>>  *
> >>>>>  * @author  naks from vpsd,Erode
> >>>>>  *   */
> >>>>> import org.postgresql.jdbc3.*;
> >>>>> import java.sql.*;
> >>>>>
> >>>>> public class ConPool {
> >>>>>        Jdbc3PoolingDataSource source = null;
> >>>>>     private Connection conn = null;
> >>>>>        /** Creates a new instance of ConPool */
> >>>>>     public ConPool() {
> >>>>>            }
> >>>>>        /** Setting the Pool which intializes the Pool to 2. */
> >>>>>     public void setPool() {
> >>>>>         // DataSource initialization
> >>>>>         System.out.println("setPool()");
> >>>>>         try {
> >>>>>             System.out.println("setting pool");
> >>>>>             // constructs a pool only when source is not assigned.
> >>>>>             // this will prevent problems if the same pool is set
> >>>>> more than
> >>>>>             // one time
> >>>>>             if (source == null) {
> >>>>>                 source = new Jdbc3PoolingDataSource();
> >>>>>                 // DataSource configuration.
> >>>>>                       source.setServerName("192.168.0.51");
> >>>>>         source.setDatabaseName("kec_test_pool");
> >>>>>         source.setUser("venbro");
> >>>>>         source.setPassword("venbro");
> >>>>>         source.setMaxConnections(2);
> >>>>>                                } else {
> >>>>>                 System.out.println("pool is set");
> >>>>>                 return;
> >>>>>             }
> >>>>>         } catch (Exception loException) {
> >>>>>             // logger.logToFile(loException);
> >>>>>             loException.printStackTrace();
> >>>>>         }
> >>>>>
> >>>>>     } //End of setPool method
> >>>>>           /**
> >>>>>      * Method inserts data to a table "test" which is like
> >>>>>      * create table test (param1 varchar(2),param2 varchar(2)) ;
> >>>>>          */
> >>>>>      public int insertDatas(){
> >>>>>            int count=-1;
> >>>>>              try{
> >>>>>                conn=source.getConnection();
> >>>>>
> >>>>>       PreparedStatement st = conn.prepareStatement("INSERT INTO
> >>>>> test values('P1','P2')");
> >>>>>            count = st.executeUpdate();
> >>>>>
> >>>>>       st.close();
> >>>>>            conn.commit();
> >>>>>       conn.close();
> >>>>>          }
> >>>>>     catch (SQLException ex) {
> >>>>>        count=0;
> >>>>>       ex.printStackTrace();
> >>>>>     }
> >>>>>        return count;
> >>>>>     }//End of Insert Method
> >>>>>               public static void main(String args[]){
> >>>>>                       ConPool cp=new ConPool();
> >>>>>         cp. setPool();
> >>>>>         int sucess_flag=cp.insertDatas();
> >>>>>         System.out.println("Sucess"+sucess_flag);
> >>>>>                /**
> >>>>>           * Upto this level the Connection pooling is working fine .
> >>>>>           * But if this Swing Component is added then it creates
> >>>>> new Connection
> >>>>>           * which is even more than the intial connection of the
> >>>>> pool..
> >>>>>          *  We have to kill the application (System.exit(0))to
> >>>>> remove the Connection
> >>>>>          ** But on commenting line :105 "Swingline " the Pool is
> >>>>> working fine..
> >>>>>                  */
> >>>>>
> >>>>> javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);//
> >>>>> Swing line 105
> >>>>>                 }
> >>>>>
> >>>>> }//End of the class
> >>>>> ##########################################################################################
> >>>>>
> >>>>> ###########################################################################################
> >>>>>
> >>>>>
> >>>>> ---------------------------(end of
> >>>>> broadcast)---------------------------
> >>>>> TIP 3: if posting/reading through Usenet, please send an appropriate
> >>>>> subscribe-nomail command to majordomo@postgresql.org so that your
> >>>>> message can get through to the mailing list cleanly
> >>>>>
> >>>>
> >>>>
> >>>> ---------------------------(end of
> >>>> broadcast)---------------------------
> >>>> TIP 5: Have you checked our extensive FAQ?
> >>>>
> >>>> http://www.postgresql.org/docs/faqs/FAQ.html
> >>>>
> >>>
> >>>
> >>> ---------------------------(end of
> >>> broadcast)---------------------------
> >>> TIP 3: if posting/reading through Usenet, please send an appropriate
> >>> subscribe-nomail command to majordomo@postgresql.org so that your
> >>> message can get through to the mailing list cleanly
> >>>
> >>
> >
> >
>
> --
> Scot P. Floess - 27 Lake Royale - Louisburg, NC  27549 - 252-478-8087
>
> Open Source Home Page
> --------------------------------------
> http://javapim.sourceforge.net
> http://jplate.sourceforge.net
> http://jwaretechniques.sourceforge.net
>
> Open Source Project Host
> -----------------------------------------------
> http://sourceforge.net/projects/javapim
> http://sourceforge.net/projects/jplate
> http://sourceforge.net/projects/jwaretechniques
>
>


Re: Help Needed with Connection Pooling for Java Swing Based

From
"Scot P. Floess"
Date:
Shan:

Can't you simply "associate" the connection with the window and when it closes, return it at the pool?   You could have a helper class who acts as a window listener and contains a connection.  When the window closes, the helper class will be called - at that time have the helper class return the connection to the pool.

Scot

Shanmugasundaram Doraisamy wrote:
Dear Derek, Scott & Barry,	   Thank you for your replies.  But, when I give the system.exit call
the whole application is closed.  This is not what I want to do.  I just
want to close only that particular form/ window alone and return the
connection to the pool.  Please let me know how this can be achieved. 
Thanking you,

Yours sincerely,

Shan.

On Thu, 2003-03-27 at 04:09, Scot P. Floess wrote: 
Derek:

I see what you mean.

Regarding needing to call System.exit...my guess is the Swing/AWT 
threads are user threads (as opposed to daemon) and that is why one must 
call System.exit()...

Scot

Derek S wrote:
   
Pardon my inaccuracy.  I should have said "Realizing" instead of 
instantiating.  "Realizing" is the name that the AWT developers gave 
to the process  (which is encapsulated in the AWT's component 
implementation) of actually allocating the system resources needed to 
display the GUI widgets.  Typically, it happens when you call pack or 
setVisible(true) on a Window, Frame or Dialog. When a component is 
realized, it checks to see if the dispatcher thread is running, and if 
not, starts it.  Depending on what you're using, it may also start 
other threads to support features like the Pluggable Look and Feel and 
so on.  As far as I know, it's only possible to have one AWT Event 
Dispatch thread.

Bringing us back to the original topic, Once the AWT threads are 
running, it's basically hit-or-miss whether the app will stop unless 
System.exit is explicitly called or you set the default close 
operation on your frame to EXIT_ON_CLOSE (which just calls System.exit 
for you), so this has nothing to do with JDBC or PostgreSQL's driver.

Scot P. Floess wrote:
     
Derek:

Are you sure instantiating a Swing component launches a new thread?  
Simply instantiating 2 JButtons will launch 2 threads?  I don't think 
that is the case.

Derek S wrote:
       
Instantiating any Swing component does in fact start a new thread - 
the AWT Event Dispatch thread.  My experience with it has been that 
this thread quite often doesn't terminate the way you might expect 
when the main method ends.  This is a well known issue that Swing 
and AWT programmers simply have to deal with and has absolutely 
nothing to do with JDBC.  Generally speaking, all Swing/AWT based 
applications call System.exit when they are finished doing whatever 
it is they do in order to ensure that the AWT Event Dispatch thread 
shuts down properly.

Barry Lind wrote:
         
I just ran your test case and everything seems to be working 
correctly as far as I can tell.  The program creates one and only 
one connection to the database.  I don't see multiple connections 
created as you are reporting.

I don't know anything about swing, but it is clear that the code 
for swing you have below isn't correct.  Because with this swing 
call the program doesn't exit.  It seems the swing code is starting 
some other threads that are running and thus the main program 
doesn't exit until those threads stop running (and I don't know 
what swing calls are necessary to stop the swing threads from 
running).

So with the swing call in place I have to ctrl-C to stop the app 
from running, but from the jdbc side of things everything seems to 
be working correctly.

Perhaps I don't understand the problem you are seeing?

thanks,
--Barry


Shanmugasundaram Doraisamy wrote:
           
Dear group,

We are having some problems when using JDBC Connection Pool using 
Postgrsql Jdbc3PoolingDataSource.

The Pool behaves fine if there is no Swing Component in the Program.
If there is a swing Component ,then the connection seems to be not 
returning to the pool and calling for an additional instance of 
the class leeds to the creation of fresh Connection objects ,at 
times it even exceeds the maximum number allowed in the pool.
If we go for System.exit(0);(Killing) then only the Connection is 
returned .

But if we comment the swing component line (here in the attached 
Program a JOptionPane is Used) then the pool behaves fine.


Herewith Iam attaching a Program which is behaving as detailed.

Any Help is Welcome.

##################################################################


##################################################################

/** ConPool.java** Created on 26 March 2003, 11:54*/

/**** @author  naks from vpsd,Erode*   */
import org.postgresql.jdbc3.*;
import java.sql.*;

public class ConPool {      Jdbc3PoolingDataSource source = null;   private Connection conn = null;      /** Creates a new instance of ConPool */   public ConPool() {          }      /** Setting the Pool which intializes the Pool to 2. */   public void setPool() {       // DataSource initialization       System.out.println("setPool()");       try {           System.out.println("setting pool");           // constructs a pool only when source is not assigned.           // this will prevent problems if the same pool is set 
more than           // one time           if (source == null) {               source = new Jdbc3PoolingDataSource();               // DataSource configuration.                     source.setServerName("192.168.0.51");       source.setDatabaseName("kec_test_pool");       source.setUser("venbro");       source.setPassword("venbro");       source.setMaxConnections(2);                              } else {               System.out.println("pool is set");               return;           }       } catch (Exception loException) {           // logger.logToFile(loException);           loException.printStackTrace();       }
   } //End of setPool method         /**    * Method inserts data to a table "test" which is like    * create table test (param1 varchar(2),param2 varchar(2)) ;        */    public int insertDatas(){          int count=-1;            try{              conn=source.getConnection();
     PreparedStatement st = conn.prepareStatement("INSERT INTO 
test values('P1','P2')");          count = st.executeUpdate();
     st.close();          conn.commit();     conn.close();        }   catch (SQLException ex) {      count=0;     ex.printStackTrace();   }      return count;   }//End of Insert Method             public static void main(String args[]){                     ConPool cp=new ConPool();       cp. setPool();       int sucess_flag=cp.insertDatas();       System.out.println("Sucess"+sucess_flag);              /**         * Upto this level the Connection pooling is working fine .         * But if this Swing Component is added then it creates 
new Connection         * which is even more than the intial connection of the 
pool..        *  We have to kill the application (System.exit(0))to 
remove the Connection        ** But on commenting line :105 "Swingline " the Pool is 
working fine..                */       
javax.swing.JOptionPane.showMessageDialog(null,"VENBRO-ERODE","MESSAGE",1);// 
Swing line 105               }
}//End of the class
##########################################################################################

###########################################################################################


---------------------------(end of 
broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
             
---------------------------(end of 
broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?

http://www.postgresql.org/docs/faqs/FAQ.html
           
---------------------------(end of 
broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
         
     
-- 
Scot P. Floess - 27 Lake Royale - Louisburg, NC  27549 - 252-478-8087

Open Source Home Page
--------------------------------------
http://javapim.sourceforge.net
http://jplate.sourceforge.net
http://jwaretechniques.sourceforge.net

Open Source Project Host
-----------------------------------------------
http://sourceforge.net/projects/javapim
http://sourceforge.net/projects/jplate
http://sourceforge.net/projects/jwaretechniques

   

 

-- 
Scot P. Floess - 27 Lake Royale - Louisburg, NC  27549 - 252-478-8087

Open Source Home Page
--------------------------------------
http://javapim.sourceforge.net
http://jplate.sourceforge.net
http://jwaretechniques.sourceforge.net

Open Source Project Host
-----------------------------------------------
http://sourceforge.net/projects/javapim
http://sourceforge.net/projects/jplate
http://sourceforge.net/projects/jwaretechniques