import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.nio.channels.FileLock;

public class FileLockTest {

    public static void main(String[] args) {

        try (

            var channel = new FileOutputStream("a.txt").getChannel())

        {

            FileLock flock = channel.lock();

            Thread.sleep();

            flock.release();

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}