Swing Application freezes in DriverManager.getConnection

[Eby George]

Hi all,
I am a newbie to Swing and Java World. I wanted to create a small swing application(as part of my project requirement) which will pull some details from the Oracle DB and display it to the user. The window just freezes on DriverManager.getConnection call and then nothing happens for a long time,until i terminate the application. The program is running fine as a stand alone Java program. But it is failing when the same is implemented in Swing. I have pasted the relevant codes. I gogled around and found several threads but could not find a solution. I am using

Netbeans 6.7.1.
Java version "1.6.0_16"
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi(the server is located on a remote Unix box).

Please let me know if any other information is needed.

/*
 * DesktopApplication2.java
 */

package desktopapplication2;

import org.jdesktop.application.Application;
import org.jdesktop.application.SingleFrameApplication;

/**
 * The main class of the application.
 */
public class DesktopApplication2 extends SingleFrameApplication {

    /**
     * At startup create and show the main frame of the application.
     */
    @Override protected void startup() {
        show(new DesktopApplication2View(this));
    }

    /**
     * This method is to initialize the specified window by injecting resources.
     * Windows shown in our application come fully initialized from the GUI
     * builder, so this additional configuration is not needed.
     */
    @Override protected void configureWindow(java.awt.Window root) {
    }

    /**
     * A convenient static getter for the application instance.
     * @return the instance of DesktopApplication2
     */
    public static DesktopApplication2 getApplication() {
        return Application.getInstance(DesktopApplication2.class);
    }

    /**
     * Main method launching the application.
     */
    public static void main(String[] args) {
        launch(DesktopApplication2.class, args);
    }
}
---------------------------------------------

The code that crea polNo object on the click of the button.

 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton1ActionPerformed
        // TODO add your handling code here:
        JOptionPane.showMessageDialog(mainPanel,jTextField1.getText());
        polNo policyNo = new polNo(jTextField1.getText());
        JOptionPane.showMessageDialog(mainPanel, policyNo.getbusProdCode() + policyNo.getprodId());
    }//GEN-LAST:event_jButton1ActionPerformed
--------------------------------------------------------------------------------------------
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package desktopapplication2;

/**
 *
 * @author ebenezer.k
 */
import java.sql.*;
import oracle.jdbc.*;

public class polNo {
private int prodId;
private String busProdCode;
private Connection connection = null;
private ResultSet rs;
private StringBuffer sql;
private Statement pst;

public polNo(String policyNo,String flag)
{
    this.prodId = 768;
    this.busProdCode = "MCY";
}


public polNo(String policyNo)
{


 if (chkOraClssFile())
 {
       try {
           System.out.print("Here");


        	connection = DriverManager.getConnection(
		"jdbc:oracle:thin:@IP:1524:SID", "uid",
		"pwd");
                System.out.print("Here");
		sql.append("Select t1.product_id,t2.biz_prdt_code ");
                sql.append("FROM T_POLICY_GENERAL T1,T_PRODUCT_GENERAL T2 ");
                sql.append("WHERE POLICY_NO = '" + policyNo + "' ");
                sql.append("AND T1.PRODUCT_ID = T2.PRODUCT_ID");
                System.out.println(sql);

                pst = connection.createStatement();
                rs = pst.executeQuery(sql.toString());

                while(rs.next()){
                this.prodId = rs.getInt("PRODUCT_ID");
                this.busProdCode = rs.getString("BIZ_PRDT_CODE");
                //System.out.println(s + " " + n);
                }
		rs.close() ;
		connection.close() ;
 }
       catch (SQLException e) {

			System.out.println("Connection Failed! Check output console");
			e.printStackTrace();
			return;

		}
 }}

private void setprodId(int productId)
{
    this.prodId = productId;
}
private void setbusProdCode(String businessProdCode)
{
    this.busProdCode = businessProdCode;

}

public int getprodId()
{
    return this.prodId;
}
public String getbusProdCode()
{
   return  this.busProdCode;

}

private boolean chkOraClssFile()
{
        try {
 	Class.forName("oracle.jdbc.OracleDriver");
        return true;

	} catch (ClassNotFoundException e) {
        System.out.println("Where is your Oracle JDBC Driver?");
        e.printStackTrace();
         return false;
	}
}
}

[Stephan van Hulst]

Hi Ebi, welcome to CodeRanch! Please UseCodeTags. I added them for you this time.

Eby George wrote:I am a newbie to Swing and Java World. [...] I am using Netbeans 6.7.1.

Here's the problem. First learn Swing before you learn how to make a Swing program in an IDE. Writing a Swing application is incredibly hard to get right if your IDE adds all sorts of code and you don't know what it does.

Have you read Oracle's Swing tutorial yet?

[Nam Ha Minh]

To avoid GUI freezing, the code that connects to database should be executed in a separate thread, other than in the event dispatching thread.

[Rob Spoor]

In other words, read Concurrency in Swing.

[Eby George]

Wow and I thot, learning Swing will be easier/faster with an IDE. Will try launching it in a seperate thread and get back with the results.

[Darryl Burke]

The Swing Application Framework (org.jdesktop... classes) isn't part of Swing. Learn to use the core Java classes first. The SAF (JSR-296) may be useful for large Swing applications, but it has its own learning curve.