JAVA: What is the error in this applet?

[Yohan Weerasinghe]

Hi all,

I have created an applet but it has some errors. The error is, the code inside the try, catch block is not working. Apart from that all other works fine. Please help me to correct this code. here is a very little part of the code.

Code:

// Java Document
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;

/*
<applet code="test.class" width=1000 height=600></applet>
*/

public class test extends JApplet implements ActionListener
{
    

    JLabel lProgram,lFirstName;



    JTextField tFirstName;



    JButton button1;


    GridBagLayout gbl;
    GridBagConstraints gbc;

        Font f = new Font("Sans Serif",Font.BOLD,30);
         Font f1 = new Font("Arial",Font.BOLD,20);

    public void init()
    {

        /*Declaring Labels*/

        
        lProgram = new JLabel("Graduation Degree Program");



        lFirstName = new JLabel("First Name");
                tFirstName = new JTextField(10);




        /*Declaring the Buttons*/
        button1 = new JButton("Continue");
                button1.addActionListener(this);


        /*Seting up the Final Window*/
        gbl = new GridBagLayout();
        gbc = new GridBagConstraints();

        JPanel panel1 = new JPanel();
        panel1.setLayout(gbl);

        gbc.anchor = GridBagConstraints.WEST;




             

                gbc.gridx = 1;
                gbc.gridy = 3;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(lProgram,gbc);
                panel1.add(lProgram);



                gbc.gridx = 1;
                gbc.gridy = 7;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(lFirstName,gbc);
                panel1.add(lFirstName);

                gbc.gridx = 2;
                gbc.gridy = 7;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(tFirstName,gbc);
                panel1.add(tFirstName);



                gbc.gridx = 2;
                gbc.gridy = 24;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(button1,gbc);
                panel1.add(button1);

                panel1.setBorder(new LineBorder(Color.BLUE));


                JPanel mPanel = (JPanel)getContentPane();
                mPanel.setLayout(new BorderLayout());
                mPanel.add(panel1);
               




    }

        public void actionPerformed(ActionEvent ae)
    {
             if(ae.getSource().equals(button1))
             {
                 if(tFirstName.getText() == null ? "" == null : tFirstName.getText().equals(""))
                 {
                     JOptionPane.showMessageDialog(null,"Please fill the first name");

                 }
                 


             }
             else
             {
                 String link = "http://www.google.com";
                 try
                {

                    AppletContext as = getAppletContext();
                    URL url = new URL(link);
                    as.showDocument(url,"_self");
                }
                catch(Exception e)
                {

                }


            }
    }


}

[Ulf Dittmer]

The first thing to do is to put an e.printStackTrace() in the catch block. You should not ignore exceptions - at the least print some information to a console or log file.

[Yohan Weerasinghe]

Ulf Dittmer wrote:The first thing to do is to put an e.printStackTrace() in the catch block. You should not ignore exceptions - at the least print some information to a console or log file.

Thanks for the reply. I did that...But no progress. I executed it in net beans, but didn't get any info regarding any error. Please help me. Here I am posting my new code

// Java Document
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;

/*
<applet code="test.class" width=1000 height=600></applet>
*/

public class test extends JApplet implements ActionListener
{
        JLabel lProgram,lFirstName;
	JTextField tFirstName;
	JButton button1;

	GridBagLayout gbl;
	GridBagConstraints gbc;

        Font f = new Font("Sans Serif",Font.BOLD,30);
         Font f1 = new Font("Arial",Font.BOLD,20);

	public void init()
	{

		/*Declaring Labels*/		
		lProgram = new JLabel("Graduation Degree Program");

		lFirstName = new JLabel("First Name");
                tFirstName = new JTextField(10);

		/*Declaring the Buttons*/
		button1 = new JButton("Continue");
                button1.addActionListener(this);

		/*Seting up the Final Window*/
		gbl = new GridBagLayout();
		gbc = new GridBagConstraints();

		JPanel panel1 = new JPanel();
		panel1.setLayout(gbl);

		gbc.anchor = GridBagConstraints.WEST;
             

                gbc.gridx = 1;
                gbc.gridy = 3;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(lProgram,gbc);
                panel1.add(lProgram);

                gbc.gridx = 1;
                gbc.gridy = 7;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(lFirstName,gbc);
                panel1.add(lFirstName);

                gbc.gridx = 2;
                gbc.gridy = 7;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(tFirstName,gbc);
                panel1.add(tFirstName);
                
                gbc.gridx = 2;
                gbc.gridy = 24;
                gbc.gridwidth= 1;
                gbc.gridheight = 1;
                gbl.setConstraints(button1,gbc);
                panel1.add(button1);

                panel1.setBorder(new LineBorder(Color.BLUE));

                JPanel mPanel = (JPanel)getContentPane();
                mPanel.setLayout(new BorderLayout());
                mPanel.add(panel1);
	}

        public void actionPerformed(ActionEvent ae)
    {
             if(ae.getSource().equals(button1))
             {
                 if(tFirstName.getText() == null ? "" == null : tFirstName.getText().equals(""))
                 {
                     JOptionPane.showMessageDialog(null,"Please fill the first name");

                 }

             }
             else
             {
                 String link = "http://www.google.com";
                 try
                {

                    AppletContext as = getAppletContext();
                    URL url = new URL(link);
                    as.showDocument(url,"_self");
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }

            }   
        }
}

[Ulf Dittmer]

I executed it in net beans,

That could be the problem. NetBeans is not a browser, so it wouldn't have a proper AppletContext. Create an HTML page with an APPLET tag, and then load that into a browser.

[Yohan Weerasinghe]

Checked that in a browser. No good.

[Ulf Dittmer]

Which means what? Which lines of code of the actionPerformed method are being executed?

[Yohan Weerasinghe]

code inside the the try catch block s not working. All other parts are OK.

[Ulf Dittmer]

Ask yourself this: Under which circumstances would the try/catch block ever be executed?

[Yohan Weerasinghe]

Ulf Dittmer wrote:Ask yourself this: Under which circumstances would the try/catch block ever be executed?

There should be no code before the opening of the try block. I removed all the form validations code and if else parts and it worked!! But the case is, that code is a must! I must check whether those given fields are empty or not before submitting the form. Actually this code is a part of my java project in my degree. I really appreciate your help. please help me. That form validation is a MUST!

[Yohan Weerasinghe]

I had to google a lot in order to find out "How to link using java". Now that is also not working as I need. please help...

[Ulf Dittmer]

Here's the clue to the solution: The if condition that currently decides whether the try/catch block is executed does NOT check the form input - it checks something else entirely.

I had to google a lot in order to find out "How to link using java". Now that is also not working as I need.

Forget about whatever you found or did there; that's not the problem.

[Yohan Weerasinghe]

Thanks for the help...I replaced the else statement and it worked! Thanks again!