CODEWITHSUNDEEP
javalocking
user3133542
user3133542

Reputation: 1715

Why I do not can delete the file?

I do not understand why Java don't want to delete the file! I basically want to lock a file to avoid that my jar-file can start more than one time. Then after the action I want to delete the lock-file, but this seems for some reason not to be possible.

Here is the code:

package footballQuestioner;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.nio.channels.FileLock;
import java.nio.file.Files;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class attempter 
{
    public static void main(String[] args) throws FileNotFoundException, IOException 
    {
        Ausgabe ausGabe=new Ausgabe();
    }

    class Ausgabe  
    {
        public Ausgabe() 
        {
           tryToStart();
        }

        public boolean tryToStart(){

            File file1=new File("C:\\Users\\laudatio\\Downloads\\erzFeind.txt");
            RandomAccessFile in=null;
            FileLock fileLock=null;
            file1.setWritable(true);

            try 
            {
               file1.createNewFile();
               in = new RandomAccessFile(file1, "rw");
               fileLock = in.getChannel().tryLock();

               if(fileLock == null)
                 return false;


            } 
            catch (Exception e) 
            {
                e.printStackTrace();
            }

        file1.delete();

        return true;
}

}

Upvotes: 1

Views: 111

Answers (1)

Peter Lawrey
Peter Lawrey

Reputation: 533442

You can't delete a file you have open. This is a limitation of Windows. You must first close it. try

file1.close();
file1.delete();

Note: Unix doesn't do this, it not a Java "feature"

Upvotes: 2

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