stop a running thread without exiting the jvm

[nikil shar]

hi all,
was wondering whats the best way of stopping a thread without exiting the JVM. I have a java programme which spawns out a few threads in the jvm , each of these threads do different things and i need to stop one of the threads when file name already exists while the other threads continue to run :

public class distributeTask {

.
.
.
   if(task = 1 ) {
          createFile fileCreate = new createFile("filename");
          fileCreate.start();
      
    }



}




public class createFile extends Thread {

.
.
.

public void run () {

     File outFile = new File("path to file");

     if(outFile.exists())
        {
                System.out.println("File  " + outfile + " already exists, terminating the thread");
                System.exit(4);  //this exits the jvm

        }

  .
  .
  .

}

}

thanks in advance.

[Paul Clapham]

Just return from the run() method.

[nikil shar]

thanks for the reply. In the distributeTask class, is there a way to detect if the fileCreate thread returned as a result of file already existing ??

[Paul Clapham]

Not the way you wrote it, no. Of course a thread is like any other class, it can provide methods to allow other objects to find out about its internal state. In your case you would write a wasFileFound() method which returns a boolean value which you set after looking for the file.

[nikil shar]

ok heres what i got so far :

public class createFile extends Thread {   
  private static boolean fileFound = false;
.   
.   
.   
  public static boolean getFileFound() {
        return packagename.createFile.fileFound;
   }


    private void setFileFound(boolean value) {
        packagename.createFile.fileFound = value;
   }

public void run () {   
  
     File outFile = new File("path to file");   
  
     if(outFile.exists())   
        {   
                System.out.println("File  " + outfile + " already exists, terminating the thread");   
                setFileFound(true);  
                return;
        }   
  
  .   
  .   
  .   
  
}   
  
}  

for some reason i always get a "new file was created" in this, even though i have manually created the file and placed it in the assumed dir :

public class distributeTask {   
  
.   
.   
.   
   if(task = 1 ) {   
          createFile fileCreate = new createFile("filename");   
          fileCreate.start();   
         
    }   
  
  if(packagename.createFile.getFileFound()){
  System.out.println("Thread found an existing file");
  } else {
  System.out.println("new file was created");
  }
  
}   
  

any suggestions what i am doing wrong ??

[Ulf Dittmer]

This looks suspicious:

if(task = 1 ) {

[nikil shar]

the task variable is just to read the input since there are multiple tasks which can be done by this class.

[nikil shar]

oh i see what you mean sorry that's a typo, it should be task == 1