ConcurrentPartialFileLocking_main.java

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.nio.channels.OverlappingFileLockException;

public class ConcurrentPartialFileLocking {
    private static final String FILENAME = "concurrent_partial_locked_file.txt";
    private static final String PHRASE = "The quick brown fox     jumped over the lazy dog.";
    private static final int FILE_SIZE = PHRASE.length();

    public static void main(String[] args) {
        createFileWithPhrase(FILENAME, PHRASE); // 1. Create the file with the phrase.

        int halfSize = FILE_SIZE / 2; // 2. Create and start two threads.
        Thread thread1 = new Thread(new FileRegionTask(FILENAME, 0, halfSize, "Thread 1"));
        Thread thread2 = new Thread(new FileRegionTask(FILENAME, halfSize, FILE_SIZE - halfSize, "Thread 2"));
        thread1.start();
        thread2.start();
        
        try { // Wait for the threads to finish.
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            System.err.println("Main thread interrupted: " + e.getMessage());
        }
    }