Multithreading and Concurrency

Multithreading is a powerful concept in Java that allows us to execute multiple threads concurrently within a single process. It enables applications to make the most of modern multi-core processors, leading to improved performance and responsiveness.

Example of Multithreading:

public class MyThread extends Thread {
public void run() {
System.out.println(“Thread is running!”);
}
}

// Usage
public static void main(String[] args) {
MyThread thread = new MyThread();
thread.start();
}

In Java, you can create threads by extending the Thread class or implementing the Runnable interface. The Runnable approach is preferred as it promotes better separation of concerns and allows you to use a single Runnable instance for multiple threads.

Example of Runnable Interface:

public class MyRunnable implements Runnable {
public void run() {
System.out.println(“Runnable is running!”);
}
}

// Usage
public static void main(String[] args) {
MyRunnable runnable = new MyRunnable();
Thread thread = new Thread(runnable);
thread.start();
}

When multiple threads access shared resources, there is a risk of data inconsistency and race conditions. Synchronization ensures that only one thread can access critical sections of code at a time, preventing conflicts and maintaining thread safety.

Example of Synchronization:

public class Counter {
private int count = 0;

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

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

Java provides a set of thread-safe concurrent collections that allow multiple threads to access them simultaneously without external synchronization. These collections offer better performance and are designed to handle concurrent scenarios efficiently.

Example of Concurrent Collection:

import java.util.concurrent.ConcurrentHashMap;

public class ConcurrentMapExample {
public static void main(String[] args) {
ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put(“A”, 1);
map.put(“B”, 2);

map.forEach((key, value) -> System.out.println(key + “: ” + value));
}
}