Issue in launching a text file on Desktop.

Hi I have an issue with following code.

This line in the code "try{Runtime.getRuntime().exec(st);}catch(IOException e1){System.out.println("Caught "+e1 );}" does not run Text file stored on Desktop in windows based computer.

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.*;
public class FileChooserDemo2 extends JPanel
                              implements ActionListener {
    static private String newline = "\n";
    //private JTextArea log;
    private JFileChooser fc;
    public FileChooserDemo2() {
        super(new BorderLayout());
        //Create the log first, because the action listener
        //needs to refer to it.
      //  log = new JTextArea(5,20);
      //  log.setMargin(new Insets(5,5,5,5));
      //  log.setEditable(false);
        JScrollPane logScrollPane = new JScrollPane();
        JButton sendButton = new JButton("Attach...");
        sendButton.addActionListener(this);
        add(sendButton, BorderLayout.PAGE_START);
        add(logScrollPane, BorderLayout.CENTER);
    }
    public void actionPerformed(ActionEvent e) {
        //Set up the file chooser.
        if (fc == null) {
            fc = new JFileChooser();
     //Add a custom file filter and disable the default
     //(Accept All) file filter.
            fc.addChoosableFileFilter(new textfilter());
            fc.setAcceptAllFileFilterUsed(false);
     //Add custom icons for file types.
     //       fc.setFileView(new ImageFileView());
     //Add the preview pane.
     //       fc.setAccessory(new ImagePreview(fc));
        }
        //Show it.
        int returnVal = fc.showDialog(FileChooserDemo2.this, "Save");
        //Process the results.
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fc.getSelectedFile();
            String pa=file.getAbsolutePath();
            /*//pa=pa.replace("\\","\\\\");
            //pa="\""+pa+"\"";
            //StringTokenizer sa=new StringTokenizer(pa, "\\\\"); 
            String[] tokens = pa.split("\\\\");
            pa="";
            for(int i=0;i<=4;i++)
            { pa=pa+tokens[i]+File.separator;
              
             // System.out.println(tokens[i]);
            }*/
            pa=pa.replace("\\","\\\\");
            pa="\""+pa+"\"";
            String st=new String(pa); 
            try{Runtime.getRuntime().exec(st);}catch(IOException e1){System.out.println("Caught   "+e1 );}
 //        [b]<--------------------------------------------------------[/b]            System.out.println(pa);
            //log.append("Saving file: " + file.getName()+ "." + newline);
        } else {
            //log.append("Save cancelled by user." + newline);
        }
        //log.setCaretPosition(log.getDocument().getLength());
        //Reset the file chooser for the next time it's shown.
        fc.setSelectedFile(null);
    }
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("FileChooserDemo2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Add content to the window.
        frame.add(new FileChooserDemo2());
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                //Turn off metal's use of bold fonts
                UIManager.put("swing.boldMetal", Boolean.FALSE);
                createAndShowGUI();
            }
        });
    }
}

What does it mean to "run" a text file? That's not executable content.

Welcome to the Ranch!

Manish Soin wrote: File file = fc.getSelectedFile(); String pa=file.getAbsolutePath(); /*//pa=pa.replace("\\","\\\\"); //pa="\""+pa+"\""; //StringTokenizer sa=new StringTokenizer(pa, "\\\\"); String[] tokens = pa.split("\\\\"); pa=""; for(int i=0;i<=4;i++) { pa=pa+tokens[i]+File.separator; // System.out.println(tokens[i]); }*/ pa=pa.replace("\\","\\\\"); pa="\""+pa+"\""; String st=new String(pa); try{Runtime.getRuntime().exec(st);}catch(IOException e1){System.out.println("Caught "+e1 );}

First of all, there is no need whatsoever to create String st like that. You can simply use pa.
Second, you cannot execute any file, only executables and batch files. Anything else needs another application to run it.

Fortunately, you don't have to do any more hard work, using java.awt.Desktop that was introduced in Java 6. That same code snippet using the new class:
That will open the file with its default application. Yes, it's that simple these days.

OK, and now the more complex version that does some actual checking:
This uses the "magic" rundll32 url.dll,FileProtocolHandler command to use to execute the file with its default application. Of course this is only available on Windows.

Also, whenever you use Runtime.exec or ProcessBuilder, make sure to have read and understood When Runtime.exec() won't. It's an old article, but still very accurate. The only difference is that when you use ProcessBuilder with a redirected error stream, you don't need to read anything from p.getErrorStream().

Also, be aware of Concurrency in Swing. If you're not careful you may end up blocking the Event Dispatcher Thread, effectively making your entire user interface not respond to anything, including repaint requests from the operating system.