Example of File Locking

package com.bruceeckel;
 
//: c12:FileLocking.java
//{Clean: file.txt}
//From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
//www.BruceEckel.com. See copyright notice in CopyRight.txt.
 
import java.io.FileOutputStream;
import java.nio.channels.FileLock;
 
public class FileLocking {
    public static void main(String[] args) throws Exception {
	FileOutputStream fos = new FileOutputStream("file.txt");
	FileLock fl = fos.getChannel().tryLock();
	if (fl != null) {
	    System.out.println("Locked File");
	    Thread.sleep(100);
	    fl.release();
	    System.out.println("Released Lock");
	}
	fos.close();
    }
}