// file locking using JDK 1.2 version of java.io.File.
// This example from the book "Just Java 1.2" page 608-610

import java.io.*;
public class exclude {

   public static void main(String a[]) throws Exception {

       File locker = new File("/tmp/mailfile.lock");
       boolean IgotIt = false;

	AcquireLockLoop: for ( ; ; ) { // repeat forever
		IgotIt = locker.createNewFile();
		if (IgotIt) { // we created the file (got the lock)
			break AcquireLockLoop;
		} else { // otherwise, sleep for a bit and try again
			System.out.println(a[0] + " didn't get file, trying again");
				Thread.sleep(3000);
		}
	}
	if (IgotIt) { // do regular work here, 
	// assured that we have sole access to the resource.
		System.out.println(a[0]+ " got the file!");
		locker.deleteOnExit();
		Thread.sleep(2000);
	}
   }
}