Java Concurrency and Multithreading

Understanding concurrency and multithreading is crucial for developing high-performance Java applications. Let’s explore the key concepts and best practices.

Creating and Managing Threads

There are two main ways to create threads in Java:

// Method 1: Extending Thread class
class MyThread extends Thread {
    public void run() {
        System.out.println("Thread is running");
    }
}

// Method 2: Implementing Runnable interface
class MyRunnable implements Runnable {
    public void run() {
        System.out.println("Thread is running");
    }
}

// Usage
MyThread thread1 = new MyThread();
thread1.start();

Thread thread2 = new Thread(new MyRunnable());
thread2.start();

Synchronization

Synchronization is essential for thread safety:

public class Counter {
    private int count = 0;

    public synchronized void increment() {
        count++;
    }

    public synchronized int getCount() {
        return count;
    }
}

ExecutorService

The ExecutorService provides a higher-level replacement for working with threads:

import java.util.concurrent.*;

ExecutorService executor = Executors.newFixedThreadPool(5);

Future<String> future = executor.submit(() -> {
    Thread.sleep(1000);
    return "Task completed";
});

try {
    String result = future.get(2, TimeUnit.SECONDS);
    System.out.println(result);
} catch (TimeoutException e) {
    future.cancel(true);
}

executor.shutdown();